JPH05267400A - Adhesive film and film carrier, and connection structure using same - Google Patents

Abstract

PURPOSE:To make the connection work done easily and to increase the connection strength when connecting a connection lead and a semiconductor element and when connecting a semiconductor device obtained by joining the semiconductor element to a film carrier and an external substrate. CONSTITUTION:First, a film carrier 3 is prepared which has connection leads 4 formed on the whole surface of one face and the plurality of through holes made in specified parts. A connection section of the connection lead 4 is extended to a specified part. A through hole-formed region of the film carrier 3 is laid on top of a land section 6 of an external substrate 5. Then, the specified through holes out of the plurality of through holes of the film carrier 3 are filled with metallic substance to form bump-like projections. Using these projections, the land section 6 of the external substance 6 and the connection leads 4 of the film carrier 3 are connected. On the other face of the film carrier 3, an adhesive film 3a is adhered. The adhesive film 3a is composed of an insulating film 3' having an adhesive layer 8 whose melt viscosity is 10<8> poise or lower at the temperature 100 deg.C higher than the glass-transition temperature of an adhesive of its own.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive film and a film carrier used for connecting a film carrier, a semiconductor element and a semiconductor device to an external substrate, and a connection structure using the same.

[0002]

2. Description of the Related Art Conventionally, to connect a semiconductor device using a film carrier to an external substrate such as a package substrate or a case (outer lead bonding), a conductive material such as copper is provided on the film carrier of the semiconductor device. Connection leads formed of metal in a linear shape are used. For example, in FIG. 24, the connection leads 4 formed on the film carrier 3 are shown.
The semiconductor device in which the semiconductor element 1 and the semiconductor element 1 are connected to each other via the bump 2 is mounted on the external substrate 5 by using the metal wiring (land portion) 6 formed on the surface of the external substrate 5 and the connection lead 4 on the film carrier 3. ing.

However, in such a mounting method, it is necessary to cut or bend the connection lead 4, workability is poor, and connection cannot be performed easily. In addition, connection lead 4
Since it has a structure protruding from the film carrier, it has poor mechanical strength and has a problem in workability. In addition, a thermal bonding method such as a solder reflow method is usually used for connecting the connection lead 4 and the land portion 6. For example, when mounting on a metal oxide transparent electrode such as a liquid crystal panel, It is necessary to preliminarily metallize the transparent electrode so that it can be soldered, and the work is complicated.

In recent years, various methods have been proposed for connecting a film carrier and an external substrate by using an anisotropically conductive film or paint, but each method has drawbacks in workability and reliability, and is different. One-way conductive film and paint are expensive,
It has the drawback of high cost. Also, due to the recent demand for miniaturization and thinning of electronic devices, higher functionality and higher density are demanded for electronic parts as well. It has the fatal drawback of not being able to do.

[0005]

As described above, each of the above-mentioned conventional techniques has drawbacks, and it is desired to solve such a problem.

The present invention has been made in view of the above circumstances, and the connection between a connection lead and a semiconductor element and the connection between a semiconductor device formed by bonding the semiconductor element to a film carrier and an external substrate. It is an object of the present invention to provide an adhesive film and a film carrier that can be easily worked at the time of, for example, and can increase the strength of a connection portion, and a connection structure using the same.

[0007]

In order to achieve the above-mentioned object, the present invention has an adhesive layer formed on one surface of a film, the adhesive layer showing fluidity when pressed under heating. The melt viscosity of the adhesive is the glass transition temperature (T
g) Adhesive film having a poise of 10 ⁸ poise or less at a temperature 100 ° C. higher than that of g) is used as a first gist, and a plurality of openings are distributed and formed in a predetermined region of the insulating film, and a predetermined amount is formed on one surface of the insulating film. The connection portion of the connection lead formed in a pattern extends to the region, on one surface or the opposite surface of the insulating film on which the connection lead is formed,
A second aspect of the invention is a film carrier, wherein the adhesive film according to claim 1, which covers at least a part of the area, is joined by utilizing the adhesive force of the adhesive layer. The conductive material with which a plurality of openings forming regions of the film carrier according to claim 2 are stacked on the connection portion with the adhesive film facing outward, and a predetermined opening among the plurality of openings is filled. Alternatively, the connection portion of the connection lead extending to the opening formation region is electrically connected to the connection portion of the external substrate or the semiconductor element, and the external substrate or the semiconductor element and the film around the electrical connection portion. A third aspect of the present invention is a connection structure in which a space between the carrier and the carrier is filled with an inflow adhesive that has flowed in through the opening in the opening forming region.

[0008]

That is, in the adhesive film, for example, a plurality of openings are distributed and formed in a predetermined area, and the connecting portion of the connecting lead is joined to the insulating film extending in the area to form a part of the film carrier. Become. The film carrier configured in this way is, for example, a bump-shaped metal formed by overlapping the opening forming region on the metal wiring (land) of the external substrate and filling a predetermined opening of the plurality of openings. The land portion of the external substrate and the connection lead of the film carrier are connected using a substance or the connection portion of the connection lead extending to the opening formation region, and in that state, the adhesive is used to form the plurality of openings. Among them, the opening not filled with the conductive material is press-fitted between the film carrier and the external substrate to fill the space between them, thereby adhering and protecting the connection portion between the land portion and the connection lead.

Next, examples will be described.

[0010]

1 is a sectional view of a connection structure (mounting structure) according to an embodiment of the present invention. In the figure, 3 is a film carrier, which is made of an insulating film having a connection lead 4 formed on one surface thereof, and to which the semiconductor element 1 is connected (mounted). More specifically, in the film carrier 3, the connection leads 4 are formed in a predetermined pattern on the entire back surface of the insulating film, and a plurality of through holes are formed in the predetermined region. The connecting portion of the connecting lead 4 extends from the connecting lead 4 to the predetermined region. As shown in FIG. 2, the through hole corresponding to the connection portion of the connection lead 4 is filled with a metal substance to form a bump-shaped protrusion 2 '. As shown in FIG. 1, the protruding tip of the bump-shaped protrusion 2 ′ has a metal wiring (land portion) on the external substrate 5.
6 is electrically connected. The film carrier 3
The glass transition temperature (Tg) of the adhesive is 1
An adhesive film 3 a made of an insulating film 3 ′ having an adhesive layer 8 having a melt viscosity of 10 ⁸ poise or less at a high temperature of 00 ° C. is adhered by the adhesive force of the adhesive layer 8.

3 and 4 are enlarged sectional views showing a method for obtaining the structure of FIG. 1, FIG. 3 is a sectional view showing a state before connection, and FIG. 4 is a sectional view showing a state after connection. In FIG.
The adhesive layer 8'supported by the insulating film 3'is provided on the side of the film carrier 3 where the connection lead 4 is formed, and the land portion 6 of the external substrate 5 and the bump-shaped protrusion are faced to each other. Crimp to join the two. By this pressure bonding, as shown in FIG. 3, the adhesive of the adhesive layer 8 is press-fitted and filled between the external substrate 5 and the film carrier 3 through the fine through holes 7 not filled with the metal substance,
The land portion 6 and the connection portion around the land portion 6 are covered and protected to stabilize electric conduction and to improve mechanical shock resistance.

The bump-shaped protrusions are, as shown in FIG.
A common bump-shaped protrusion may be provided over the plurality of through holes 7.

FIG. 6 shows a connection structure of another embodiment of the present invention. That is, in this embodiment, the film carrier 3 of FIG. 1 is turned upside down, the connecting portion extending from the connecting lead 4 is made to face the land portion 6 of the external substrate 5, and in this state, the land portion 6 and the connecting lead 4 are connected by pressure contact. Then, the adhesive 8 of the adhesive film 3a provided on the surface-side portion of the film carrier 3 is cast from the fine through holes 7 of the film carrier 3 to the periphery of the connection site, and the periphery of the connection site is covered. There is. The connection between the film carrier 3 and the land portion 6 of the external substrate 5 will be described in more detail. For this connection, as shown in FIGS. 7 and 8, the connection portion of the connection lead 4 of the film carrier 3 is connected to the external substrate 5. Align with the land portion 6. Then, in this state, the connection portion of the film carrier 3 is overlaid on the land 6, and pressure is applied from the surface side of the film carrier 3. As a result, the adhesive 8 on the back surface side of the adhesive film 3a is press-fitted from the fine through holes 7 of the film carrier 3 as shown in FIGS. 9 and 10, filling the bonding gap between the film carrier 3 and the external substrate 5, Cover and protect the connection site and its surroundings. 7 and 9 are sectional views in a direction parallel to the connecting lead 4 direction, and FIGS. 8 and 10 are sectional views in a direction perpendicular to the connecting lead 4 direction. Further, in FIG. 6, the semiconductor element 1 and the connection lead 4 are connected by the metal substance 2'filled in the fine through holes 7 provided in the film carrier 3, but this part is connected by a conventional method, for example, Alternatively, bumps as shown in FIG. 5 may be used.

FIG. 11 shows still another embodiment of the present invention. In this embodiment, a long hole-shaped cut-out opening having a large opening area is formed in a predetermined region of the film carrier 3 so as to pass through the connection lead 4 as well, and the semiconductor element 1 is connected to the film carrier 3 via the bump 2. Connected to.
Other than that, it is substantially the same as FIG. More specifically, the film carrier 3 has a structure shown in FIG.
As shown in FIG. 3, an elongated cutout opening is provided so as to penetrate the connection portion of the connection lead 4 as well, and this portion is made to face the land portion 6 of the external substrate 5, and in that state, the film carrier 3 Heat and press from the side. As a result, the adhesive 8 of the adhesive film 3a is injected into the gap between the film carrier 3 and the external substrate 5 through the cutout opening as shown in FIGS. 14 and 15, and covers and protects the connection site and its periphery. .. 12 and 14 are cross-sectional views in the direction parallel to the direction of the connecting lead 4, and FIGS. 13 and 15 are cross-sectional views in the direction perpendicular thereto. In addition, in FIG.
18, 20 and 22 are sectional views showing a part of the shape of the cutout opening or the end cutout portion of the insulating film of the film carrier used in the method of the present invention, and FIGS.
9, FIG. 21 and FIG. 23 are plan views thereof.

In the present invention, the material of the film carrier 3 and the insulating film 3'is not particularly limited as long as it is a film having an electric insulating property. For example, polyester resin, epoxy resin, urethane resin. , Polystyrene resin, Polyurethane resin, Polyethylene resin, Polyamide resin, Polyimide resin, Acrylonitrile-butadiene-styrene (ABS) copolymer resin, Polycarbonate resin, Silicone resin, etc. Examples include resin series. Of these, a polyimide resin is preferably used from the viewpoint of heat resistance and mechanical strength.

The connection lead 4 formed on one surface of the film carrier 3 is made of various metals such as gold, silver, copper, nickel, cobalt, tin, lead and indium, and various alloys containing these as main components. It is formed of a conductive material and is electrically connected to the land portion (metal wiring) 6 on the external substrate 5, so that a desired function of a semiconductor element mounted in a semiconductor device can be exhibited. Wired in a pattern.

The fine through holes 7 provided in the film carrier 3 are important ones for connecting the connection leads 4 and the land portion (metal wiring) 6 on the external substrate 5 and for press-fitting the adhesive. In the bonding region of the film carrier 3 that is in contact with the land 6 on the external substrate 5 and in the vicinity thereof, a plurality of holes are provided in the thickness direction with a pitch between holes smaller than the width of the connection leads 4. The fine through holes 7 can be provided with an arbitrary hole diameter and hole pitch by using a method such as mechanical processing, laser processing, optical processing, and chemical etching. For example, excavation processing is performed by irradiation with excimer laser. Is desirable. In addition, it is possible to increase the number of through holes in contact with the connection leads 4 by increasing the hole diameter of the fine through holes 7 to the extent that adjacent through holes are not connected to each other and further reducing the pitch between holes as much as possible. This is preferable in reducing the electric resistance of the metal substance to be filled.

The fine through holes 7 provided as described above.
Among them, the through hole provided in the bonding area,
It is filled with a metal substance 2'such as solder, and the front and back surfaces of the film carrier 3 made of an insulating film are electrically connected. Furthermore, bump-like protrusions as shown in FIG. 2 are formed on the surface of the fine through-hole 7 filled with the metal substance 2 ′, which is opposite to the contact surface of the connection lead 4, at a height of several μm to tens of μm. Has been formed.

The filling of the metal substance 2'into the fine through holes 7 and the formation of bump-like protrusions can be selectively performed only in the through holes in the bonding region by, for example, electrolytic plating using the connection leads 4 as electrodes. It In the method of the present invention, the film carrier 3 is provided via the bump-shaped protrusions.
The upper connecting lead 4 is connected to the land portion 6 on the external substrate 5 by a normal electrical connecting means such as thermal bonding to mount the semiconductor device, so that electrical conduction can be obtained and the fine through hole is formed. The adhesive is pressed into the gap between the external substrate 5 and the film carrier 3 made of an insulating film through 7 to protect and fix the connection site.

As the adhesive used for the adhesive film 3a in the method of the present invention, epoxy resin, phenoxy resin, urethane resin, polystyrene resin, polyethylene resin, polyester resin, polyamide resin,
Thermosetting resin or thermoplastic resin such as polyimide resin, polycarbonate resin, silicone resin, acrylic resin, and phenol resin can be used, that is, Tg
There is no particular limitation as long as the melt viscosity at a temperature higher by 100 ° C. is 10 ⁸ poise or less.

The adhesive material may be blended with styrene-butadiene (SBR) type synthetic rubber, fluororubber, or the like. Further, thermoplastic polyimide may be used. Among these, those having a melt viscosity of 10 ⁵ poise or less at a temperature 100 ° C. higher than Tg are preferable in terms of ease of flow during press fitting and reliability after connection. Specific examples of such an adhesive material include epoxy resin, phenoxy resin, polyester resin, and polyimide resin.

Further, resins such as wholly aromatic polyimide and completely cured epoxy resin having a melt viscosity of more than 10 ⁸ poise at a temperature 100 ° C. higher than Tg are difficult to press into from the fine holes, and the external substrate The wettability with is also insufficient and it is difficult to connect and bond.

Next, this specific example will be described.

[0024]

Specific Examples 1 to 4 Resins having different melt viscosities shown in Tables 1 and 2 below were applied to one side of a polyimide film having a thickness of 25 μm to a thickness of 15 μm, respectively, and FIG.
By the method shown in FIGS. 8 and 13, samples for adhesion to various external substrates were obtained.

[0025]

Comparative Example A polyimide having a Tg of 267 ° C. and a melt viscosity at 367 ° C. of 2 × 10 ⁹ poise was used as a resin, and was adhered to an external substrate.

The melt viscosities in Tables 1 and 2 below are values at a temperature 100 ° C. higher than the glass transition temperature (Tg) of the resin used.

[0027]

[Table 1]

[0028]

[Table 2]

Next, when the sample was bonded to an external substrate by heat and pressure using a hot press, the samples of Examples 1 to 4 were able to completely shield the connection leads 4, lands 6 and connection sites from the outside air. At the same time, conduction was stable, and high reliability could be obtained. On the other hand, in the comparative example, the resin was not completely injected through the fine holes and was peeled off at the interface between the external substrate 5 and the film carrier 3 forming the semiconductor device after the hot pressing.

Any method may be used as the method of press-fitting the adhesive as long as the adhesive is injected into the fine through-holes 7. It is preferable to use a hot press method in which fluidity is increased by heating and press-fitting is performed. The conditions for hot pressing are pressure 5 to 5
00 kg / cm ² , preferably 20 to 300 kg / cm
² , (about 5 to 100 kg / cm ² when the external substrate 5 is made of a brittle material such as glass), temperature 50 to 400
℃, preferably 100-200 ℃, time 10-600
Seconds, preferably 10 to 120 seconds. Further, as shown in FIG. 3, the adhesive is preferably used in the form of a film from the viewpoint of workability and accuracy of injection amount.

When the semiconductor device is mounted by press-fitting the adhesive in this manner, the connection lead, the land portion, and the connection portion can be completely shielded from the outside air, so that high reliability can be obtained.

[0030]

As described above, according to the connection mechanism of the present invention, when the film carrier is connected to the external substrate or the semiconductor element, a plurality of through holes are provided in the insulating film in the bonding region and in the vicinity thereof. The conductive substance filled in the connection portion of the connection lead of the film carrier or the opening portion of the through hole thereof is brought into contact with the connection portion of the external substrate or the semiconductor element, and in that state, an adhesive is injected through the opening portion, Filling the space. Therefore,
There is no need to cut or bend the connecting leads as in the past, which facilitates connection and mounting work. In addition, since the connecting lead does not have a structure protruding from the film carrier unlike the conventional structure in the connecting portion with the land portion of the external substrate, the mechanical strength is excellent, and the adhesive is used in the connecting portion or its periphery. Since it is press-fitted into the portion and the portion is cut from the outside air and the coating is protected, the strength against mechanical shock and thermal shock is increased and the reliability is increased. In addition, since it is not necessary to use a relatively expensive anisotropically conductive film or paint, it is possible to keep the cost low. Moreover,
The connection area can be freely designed by selecting the size of the through hole, the size of the through hole and the cutout opening, and the formation pitch thereof. Not only can the connection area be reduced, but the connection of the fine pitch pattern is also reliable. It can be achieved easily. In addition, the film carrier and the adhesive film of the present invention have the advantages of easy handling and low manufacturing cost when forming the above-mentioned connection structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a connection structure of the present invention.

FIG. 2 is a partial cross-sectional view of an insulating film having bump-shaped protrusions formed by filling a through hole with a metal substance.

3 is a partial enlarged cross-sectional view showing a method for obtaining the structure of FIG.

FIG. 4 is a partially enlarged cross-sectional view showing the connection state.

FIG. 5 is a cross-sectional view of another example of forming bump-shaped protrusions.

FIG. 6 is a cross-sectional view of another example of the connection structure of the present invention.

FIG. 7 is a cross-sectional view of a film carrier on a land portion of an external substrate in a direction parallel to a connecting lead direction.

FIG. 8 is a sectional view in a direction perpendicular to the connection lead direction.

9 is a cross-sectional view in a direction parallel to the connection lead direction in a state where the film carrier of FIG. 7 is bonded to an external substrate.

FIG. 10 is a sectional view in a direction perpendicular to the connection lead direction.

FIG. 11 is a cross-sectional view of still another embodiment of the connection structure of the present invention.

FIG. 12 is a sectional view of still another embodiment of the film carrier connection structure.

FIG. 13 is a sectional view in a direction perpendicular to the connection lead direction.

FIG. 14 is a cross-sectional view in a direction parallel to the connection lead direction in a state where the film carrier is adhered to the land portion of the external substrate.

FIG. 15 is a sectional view in a direction perpendicular to the connection lead direction.

FIG. 16 is a cross-sectional view showing an example of the shape of the notch or opening of the insulating film used in the method of the present invention.

FIG. 17 is a plan view thereof.

FIG. 18 is a cross-sectional view showing an example of the shape of a cutout portion or an opening portion of the insulating film used in the method of the present invention.

FIG. 19 is a plan view thereof.

FIG. 20 is a cross-sectional view showing an example of the shape of a cutout portion or an opening portion of an insulating film used in the method of the present invention.

FIG. 21 is a plan view thereof.

FIG. 22 is a cross-sectional view showing an example of the shape of a cutout portion or an opening portion of an insulating film used in the method of the present invention.

FIG. 23 is a plan view thereof.

FIG. 24 is a cross-sectional view showing a conventional example.

[Explanation of symbols]

 1 Semiconductor Element 2'Metallic Material 3 Film Carrier 3'Insulating Film 4 Connection Lead 5 External Board 6 Land 7 Through Hole 8 Adhesive

Claims (5)

[Claims] 1. An adhesive layer having fluidity when pressed under heating is formed on one surface of a film, and the melt viscosity of the adhesive in the adhesive layer is determined by the glass transition temperature (T) of the adhesive.
An adhesive film which is 10 ⁸ poise or less at a temperature 100 ° C. higher than g). 2. A plurality of openings are distributed and formed in a predetermined area of the insulating film, and a connection portion of a connection lead formed in a predetermined pattern on one surface of the insulating film extends to the area, and the connection lead is formed. The adhesive film according to claim 1 is bonded to one surface or the opposite surface of the insulating film on which at least a part of the region is covered by utilizing the adhesive force of the adhesive layer. A film carrier characterized in that 3. The film carrier according to claim 2, wherein the plurality of openings are distributed and formed in the vicinity of the connection lead connecting to the connection portion of the external substrate. 4. The film carrier according to claim 2, wherein the opening is a through hole, an end notch or a notch opening. 5. A plurality of opening forming regions of the film carrier according to claim 2 are overlapped on a connection portion of an external substrate or a semiconductor element with the adhesive film facing outward.
A conductive material filled in a predetermined opening of the plurality of openings or a connecting portion of a connecting lead extending to the opening forming region is electrically connected to the external substrate or the connecting portion of the semiconductor element. In the vicinity of the electrical connection portion, a space between the external substrate or the semiconductor element and the film carrier is filled with an inflow adhesive that has flowed in through the opening of the opening forming region. Connection structure.