JPH10199934A - Semiconductor element mounting structure and semiconductor element mounting method - Google Patents

Abstract

(57) Abstract: A semiconductor element mounting structure which realizes a flip chip attach mounting method using an anisotropic conductive film without forming a gold bump on an electrode pad of a semiconductor element to reduce cost. And a semiconductor element mounting method. In a flip-chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, an electrode on which no bump is formed is arranged on the semiconductor element. In the mounting surface area on the circuit board facing the semiconductor element, the protruding connection pad portions 11, 12, and 13 are juxtaposed at positions facing the respective electrodes, and the respective protruding connection pad portions are provided. 1
It is characterized in that the electrodes 1, 12, 13 and the respective electrodes 15 are connected by conductive particles 10 inherent in the anisotropic conductive film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor element mounting structure in which a semiconductor element is connected and mounted on a circuit board by a flip chip attachment method using an anisotropic conductive film, and a semiconductor element mounting method.

[0002]

2. Description of the Related Art Consumer equipment, especially portable information terminal equipment such as notebook personal computers, portable telephones, PHSs, PDAs, etc., is increasingly required to have high-density mounting. In order to cope with this, the so-called bare chip mounting system, in which the semiconductor element is directly mounted on a substrate, is becoming the mainstream from the conventional package semiconductor mounting for mounting the semiconductor element in these devices. Also, with the miniaturization of equipment, cameras,
As can be seen from the example, the type, combination, and assembling of the mounting members become complicated, and a flexible printed board is often used as a board. In many cases, it is necessary to mount a semiconductor element also on this flexible printed circuit board in order to cope with higher functionality and higher density mounting of products.

The conventional bare chip mounting method is as follows: (1) A semiconductor chip 21 is adhered to a circuit board 22 face up, a pad between the semiconductor chip 21 and a pad of the circuit board 22 is connected by a gold wire 23, and a potting resin 24 is used. A method of sealing (shown in FIG. 12) and a method of (2) connecting a chip to a circuit board face-down by using solder, a conductive adhesive, an anisotropic conductive film or the like as a connection material (flip chip) Attach method).

The former method requires a pad area for wire bonding in addition to the chip area, whereas the latter method requires only the chip area for the mounting area of the circuit board 22. The following flip-chip attach method has been proposed.

(2-1) Soldering method: semiconductor chip 21
A barrier metal 26 is formed on the aluminum electrode 25 of the above, and the circuit board 22 and the semiconductor chip 21 are connected by solder 27. Next, a resin 28 is filled in the gap between the semiconductor chip 21 and the circuit board 22 and hardened (shown in FIG. 13).

(2-2) Conductive adhesive method: A gold bump 29 is formed on an aluminum electrode 25 of a semiconductor chip 21 by a wire bump method. Next, a conductive adhesive 30 is applied to the tip of the gold bump 29 and adhered to the circuit board 22. Finally, a resin 28 is filled in the gap between the semiconductor chip 21 and the circuit board 22 and hardened (as shown in FIG. 14).

(2-3) Anisotropic conductive film method: A semiconductor chip 21 in which gold bumps 29 are formed on an aluminum electrode 25 by a wire bump method, a plating method or the like, and a circuit board 22 are interposed via an anisotropic conductive film 31. Thermocompression bonding (Fig. 1
It is shown in FIG. ).

[0008] Among the above flip chip attach methods, the anisotropic conductive film method is the most advantageous method in that the number of steps is small and the completion time is short.

FIG. 16 shows a connection assembly diagram of the anisotropic conductive film system. An anisotropic conductive film is attached to the connection terminal of the circuit board 22. Next, after positioning the semiconductor chip 21 having the gold bump 29 formed on the aluminum electrode 25 by a wire bump method, a plating method, or the like, the semiconductor chip 21 is pressure-bonded to the circuit board 22 by a heating head. By this heat compression bonding, the gold bump electrodes 29 of the chip and the connection pads of the circuit board are electrically connected via conductive particles. Since the conductive particles other than the connection portion do not receive the pressure, the original dispersion state is maintained and the insulation between the adjacent electrodes is secured.

[0010]

As described above, the flip-chip attach mounting method of a semiconductor element using an anisotropic conductive film has a small number of steps and a short construction time, and is industrially advantageous and practical. It is a high method. However, in the conventional method, it is necessary to form a gold bump on the electrode pad of the semiconductor element, and there is a problem that the cost is increased.

[0011] An object of the present invention is to solve the above problems.
Provided is a semiconductor element mounting structure and a semiconductor element mounting method which realize a flip chip attach mounting method using an anisotropic conductive film without forming a gold bump on an electrode pad of a semiconductor element and reduce cost. It is in.

[0012]

In order to achieve the above object, the present invention relates to a flip-chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film. Is formed by arranging a plurality of electrodes on which no bumps are formed, and a plurality of projecting connection pad portions are arranged in a position facing the respective electrodes in a mounting surface region on a circuit board facing the semiconductor element. A semiconductor element mounting structure, wherein each of the protruding connection pad portions and each of the electrodes are connected by conductive particles inherent in the anisotropic conductive film.

Further, according to the present invention, in a flip-chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, the semiconductor element is provided with a plurality of electrodes on which no bumps are formed. In the mounting surface area on the circuit board facing the semiconductor element, a plurality of connection pad portions are arranged in parallel at positions facing each other by narrowing a gap with respect to each of the electrodes, and between the connection pad portions and each of the electrodes. Are connected by conductive particles inherent in the anisotropic conductive film.

Further, according to the present invention, in a flip-chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, the semiconductor element is provided with a plurality of electrodes on which no bumps are formed. In the mounting surface area on the circuit board facing the semiconductor element, a plurality of projecting connection pads connected to each of the plurality of wiring patterns are arranged in parallel at positions facing the respective electrodes. A semiconductor element mounting structure characterized in that a protruding connection pad portion and each of the electrodes are connected by conductive particles inherent in the anisotropic conductive film.

The present invention also provides a flip chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board using an anisotropic conductive film, wherein the semiconductor element is provided with a plurality of electrodes on which no bumps are formed. And a plurality of connection pad portions connected to each of the plurality of wiring patterns in a mounting region on the circuit board facing the semiconductor element and protruding by locally deforming the connection pads at positions facing the respective electrodes. A semiconductor element mounting structure, wherein each of the protruding connection pad portions and each of the electrodes are connected by conductive particles inherent in the anisotropic conductive film.

Further, according to the present invention, in a flip-chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, the semiconductor element is provided with a plurality of electrodes on which no bumps are formed. In the mounting region on the circuit board facing the semiconductor element, only a plurality of connection pad portions connected to the lower layer are arranged in parallel at positions facing the respective electrodes, and between the respective connection pad portions and the respective electrodes. Are connected by conductive particles inherent in the anisotropic conductive film.

Further, according to the present invention, a semiconductor element having a plurality of electrodes on which no bumps are formed and a connection pad portion formed of a conductor deformed in a protruding shape on the side of the semiconductor element face each of the electrodes. A semiconductor element mounting structure characterized in that a plurality of circuit boards arranged side by side are connected and bonded via an anisotropic conductive film.

Further, the present invention provides a step of attaching an anisotropic conductive film to a flexible circuit board, and a step of attaching the flexible circuit board to which the anisotropic conductive film is attached to an electrode having no bump. A plurality of semiconductor elements arranged side by side are mounted in alignment with each other, and the flexible circuit board mounted on the semiconductor elements in the mounting step is formed in correspondence with the arrangement of the respective electrodes. By pressing a heating head having a plurality of projections, a conductor formed on the flexible circuit board is deformed into a projection shape to form a plurality of connection pad portions, and the difference between each connection pad portion and each of the electrodes is made. A heating head pressing step of connecting with conductive particles present in the isotropic conductive film.

The present invention also provides an anisotropic conductive film adhering step of adhering an anisotropic conductive film to a semiconductor element having a plurality of electrodes on which no bumps are formed, and a flexible circuit board, A mounting step of aligning and mounting the film on the semiconductor element, and a plurality of flexible circuit boards formed on the flexible circuit board mounted on the semiconductor element in the mounting step in correspondence with the arrangement of the electrodes. By pressing a heating head having protrusions, the conductor formed on the flexible circuit board is deformed into a protrusion shape to form a plurality of connection pad portions, and the connection pad portions and the electrodes are anisotropically. And a heating head pressing step of connecting with conductive particles existing in the conductive film.

Further, the present invention provides a method of connecting a semiconductor element having a plurality of electrodes on which no bumps are formed side by side and a circuit board having a plurality of connection pads having projections made of conductors by an anisotropic conductive film. A semiconductor element mounting structure characterized by being bonded.

Further, the present invention is characterized in that in the semiconductor element mounting structure, the projection made of the conductor is formed of a cured product of a conductive adhesive.

Further, the present invention is characterized in that in the semiconductor element mounting structure, the projection made of the conductor is formed of a metal material.

Further, according to the present invention, a semiconductor element having a plurality of electrodes having no bumps formed thereon and a circuit board having a plurality of connection pads formed on via holes are connected and bonded by an anisotropic conductive film. This is a semiconductor element mounting structure characterized by being configured as described above.

As described above, according to the above-described configuration, each of the plurality of electrodes arranged in parallel with the semiconductor element is formed on the circuit board without forming gold bumps on the plurality of electrodes arranged in parallel with the semiconductor element. The connection between the connection pads and the connection pads corresponding to the electrodes can be performed by applying pressure mainly by the conductive particles inherent in the anisotropic conductive film while receiving pressure mainly, thereby enabling connection with low resistance. Thus, it is possible to realize a semiconductor bare chip mounting with extremely low cost and high reliability. That is, the conductive particles are pressurized only at the connection portion where the electrode and the connection pad portion in the mounting surface region where the semiconductor element faces are opposed, and the conductive particles are not pressed at a portion other than this connection portion, so that good low resistance is obtained. Can be connected.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION A method of flip-chip attach-mounting a semiconductor device without bumps according to the present invention (hereinafter, referred to as a bumpless semiconductor chip) to a circuit board using an anisotropic conductive film (hereinafter, referred to as a bumpless semiconductor chip). An embodiment of the present invention will be described with reference to the drawings.

First, a first embodiment according to the present invention will be described with reference to FIGS.

In the first embodiment, when the flexible printed circuit board and the padless semiconductor chip are thermocompression-bonded via an anisotropic conductive film, the electrode position of the padless semiconductor chip is located at the tip of the thermocompression bonding head. In this case, a projection corresponding to the size is formed, and only the electrode position is applied, and the padless semiconductor chip is mounted on a flexible printed board with a bare chip using an anisotropic conductive film.

FIG. 3 is a perspective view showing one embodiment of the thermocompression bonding head used in the first embodiment according to the present invention. FIG. 4 is a partially enlarged view showing a case where a protrusion formed on a thermocompression bonding head is formed in a square shape, and FIG. 5 is a partially enlarged view showing a case where a projection formed on a thermocompression bonding head is formed in a circular shape. is there. That is, the overall size of the thermocompression bonding head 5 according to the present invention is substantially the same as the size of the bumpless semiconductor chip (bumpless semiconductor element) 1 to be used,
Or made to a little bit larger. The tip of the head 5 is provided with Al disposed on the bumpless semiconductor chip 1.
The required number of protrusions 4 are formed corresponding to the electrodes 15 such as. The size of the projection 4 may be slightly larger than the size of the electrode 15 of the half bumpless conductor chip 1, but if it is too large, a connection failure occurs.
Accordingly, the size of the protrusion 4 is determined by the bumpless semiconductor chip 1.
It is preferable that the size is equal to or smaller than the size of the electrode 15. Protrusion 4
Varies depending on the total film thickness (base material, cover material, copper foil wiring pattern) of the flexible printed circuit board 2a to be used, but is generally from 0.003 mm to
It is preferably about 0.3 mm. On the other hand, if the height of the projections 4 is larger than the total film thickness of the flexible printed circuit board 2a to be used, the heating and pressing head 5 and the flexible printed circuit board 2a do not come into contact with each other, so that heat is not transmitted to the anisotropic conductive film 3. , The epoxy resin does not cure. Therefore, it is preferable that the height of the protrusions 4 formed on the thermocompression bonding head 5 be equal to or less than the total film thickness of the flexible printed circuit board 2a to be used. The shape of the projection 4 of the head is not particularly limited, and can be selected from a square 4a shown in FIG. 4, a circle 4b shown in FIG. In addition, the protrusion 4 can be tapered as required.

The protrusions 4 in the thermocompression bonding head 5 can be easily manufactured by an etching method or the like.

Next, a method of connecting and mounting the bumpless semiconductor chip 1 to the flexible printed circuit board 2a which is a circuit board by the bumpless flip chip attach mounting method will be described.

The flexible substrate 2a is formed by forming a wiring pattern 8 on a flexible base material 7. Then, a connection pad portion is formed at an end of each wiring pattern 8.

The anisotropic conductive film 3 is formed of a film in which conductive particles 10 are dispersed in an uncured epoxy resin 9. As the conductive particles, metal particles such as nickel, metal particles such as nickel plated with gold, or particles obtained by forming a nickel film and a gold plating film on plastic particles are often used.

The conditions of the thermocompression bonding by the thermocompression bonding head 5 are slightly different depending on the anisotropic conductive film 3 to be used, but are about 170 to 200 ° C., about 5 to 20 seconds, about 5 to 400 MPa.
a (pressure per unit area of the center portion of the projection 24) is preferable. When the pressure is lower than about 5 MPa, the conductive particles of the anisotropic conductive film 3 may not be deformed and a good connection state may not be obtained. If the pressure is higher than about 400 MPa, the bumpless semiconductor chip 1 may be broken. If necessary, a method of inserting a cushion material such as a silicone resin, a Teflon resin, a metal film, or the like between the thermocompression bonding head 5 and the flexible printed circuit board 2a and performing compression bonding may be employed.

There are the following two methods for the thermocompression bonding using the thermocompression head 5, and any of them can be adopted.

(A) As shown in FIG. 6, an anisotropic conductive film 3 is pasted on a bumpless semiconductor chip 1, mounted on a flexible printed circuit board 2a, and then thermocompression-bonded using the thermocompression head 5. how to.

(B) As shown in FIG. 7, the anisotropic conductive film 3 is pasted on the flexible printed board 2a, the bumpless semiconductor chip 1 is mounted thereon, and the thermocompression bonding head 5 is used for thermocompression bonding. how to.

FIG. 1 shows a thermocompression bonding state by the thermocompression bonding head 5. As shown in FIG. 1, the anisotropic conductive film 3 is pasted on the bumpless semiconductor chip 1 or the flexible printed circuit board 2a, and then the bumpless semiconductor chip 1 is aligned and mounted on the surface plate 6, ,
Using a heating / compression bonding head 5 in which the projections 4 are provided at positions corresponding to the chip electrodes 15 of Al or the like, from the flexible printed board 2a side to the bumpless semiconductor chip 1 side, about 1
When thermocompression bonding is performed at 70 to 200 ° C. for about 5 to 20 seconds and about 5 to 400 MPa, wiring is performed together with the base member 7 in a portion facing the chip electrode 15 on the flexible printed circuit board 2 a according to the shape of the projection 4. Pattern (conductor)
The connection pad portion 8 is deformed into a protruding shape, and the deformed protruding connection pad portion 14 and the chip electrode 15 are electrically connected by the conductive particles 10 with a low resistance value and the epoxy resin 9 is cured. Will be implemented. Then, since the conductive particles other than the connection portion do not receive the pressure, the original dispersion state is maintained, and the insulation between the adjacent electrodes is ensured. Thus, the semiconductor element mounting structure shown in FIG. 2 can be obtained. As shown in FIG. 2, the flexible printed board 2a has a concavely deformed structure, but there is no practical problem.

Next, the first embodiment described above will be described more specifically as an example.

[0039]

Example 1 The following test chip was used as a padless semiconductor chip.

Size: 8 mm square Thickness: 0.45 mm Connection pad size: 0.105 × 105 mm Connection pad pitch: 0.13 mm Connection arrangement: 4 sides of the periphery The flexible printed board 2 a has a two-layer wiring structure flexible board ( (About 0.075 mm thick). The copper wiring used had a thickness of about 0.035 mm. The wiring width of chip connection is about 0.09mm, and the space between wirings is about 0.04mm
And The wiring of the test chip 1 and the flexible printed board 2a was designed so that the connection resistance could be measured by the four-terminal method.

A gold-plated nickel conductive particle having a thickness of about 0.2 to 0.3 μm and a diameter of about 0.008 mm, and an uncured epoxy resin are applied to the chip connection area of the flexible printed circuit board 2 a (mixing ratio is volume 10: 90 ~
(Approximately 20:80). Next, the above-mentioned bad semiconductor chip 1 was aligned and mounted. Next, about 0.08 mm square, height about 0.07
Using a thermocompression bonding head 5 provided with a 5 mm projection 4 at a position corresponding to the chip electrode, heat was applied from the flexible printed circuit board side to the chip side. As a result, the connection pad portion of the wiring pattern (conductor) 8 is deformed into a protruding shape, and a connection is made between the deformed protruding connection pad portion 14 and the chip electrode 15 by the conductive particles 10 and the epoxy resin 9 is cured. Will be implemented. The crimping temperature was about 200 ° C., the time was about 20 seconds, and the pressure per unit area of the tip of the projection 4 was about 100 MPa. The connection resistance of the connection terminal was about 25 mΩ on average, and a sufficiently low resistance value was obtained.

[0042]

Example 2 The same members as those in Example 1 were used for the padless semiconductor chip 1 and the flexible printed circuit board. 0.2-0.3μ on the entire surface of the semiconductor chip on the electrode side
Approximately 0.008mm in diameter with gold plating of about m thickness
Nickel conductive particles and uncured epoxy resin (the mixing ratio of conductive particles and uncured epoxy resin is 10: 9 by volume ratio)
0-20: 80) was attached. Next, the chip 1 was aligned and mounted on the flexible printed circuit board 2a. Next, a diameter of about 0.08
Using a thermocompression bonding head 5 provided with a protrusion 4 having a height of about 0.050 mm and a height of about 0.050 mm at a position corresponding to the chip electrode, heat was applied from the side of the flexible printed board to the side of the chip. As a result, the connection pad portion of the wiring pattern (conductor) 8 is deformed into a protruding shape, and the deformed protruding connection pad portion 1 is deformed.
4 and the chip electrode 15 are connected by the conductive particles 10 and the epoxy resin 9 is cured and mounted. Crimping temperature is about 200 ° C, time is about 20
Second, the pressure per unit area of the tip of the projection 4 is about 200M
Performed at Pa. The connection resistance of the connection terminal was about 30 mΩ on average, and a sufficiently low resistance value was obtained.

[0043]

Embodiment 3 The same members as those in Embodiment 1 were used for the padless semiconductor chip 1 and the flexible printed circuit board 2a. A nickel conductive particle having a diameter of about 0.008 mm and an uncured epoxy resin and a gold plating having a thickness of about 0.2 to 0.3 μm are applied to a chip connection region of a flexible printed circuit board. An anisotropic conductive film 3 having a mixing ratio of about 10:90 to 20:80 by volume) was attached. Next, the chip 1 was aligned and mounted. Next, using a thermocompression bonding head 5 provided with a projection having a diameter of about 0.08 mm and a height of about 0.050 mm at a position corresponding to the chip electrode, the thermocompression bonding was performed from the flexible printed board side to the chip side. As a result, the connection pad portion of the wiring pattern (conductor) 8 is deformed into a protruding shape, and a connection is made between the deformed protruding connection pad portion 14 and the chip electrode 15 by the conductive particles 10 and the epoxy resin 9 is cured. Will be implemented. The compression temperature was about 200 ° C., the time was about 20 seconds, and the pressure per unit area of the tip of the projection 4 was about 200 MPa. The connection resistance of the connection terminal was about 30 mΩ on average, and a sufficiently low resistance value was obtained.

[0044]

Embodiment 4 The same members as those in Embodiment 1 were used for the padless semiconductor chip 1 and the flexible printed circuit board 2a. Nickel plating film (thickness of about 0.3 to 0.6 μm) and gold plating film (thickness of about 0.2 to 0.1 μm) on the surface of plastic particles with a diameter of about 0.005 mm in the chip connection area of the flexible printed circuit board The conductive particles and the uncured epoxy resin formed with (the mixing ratio of the conductive particles and the uncured epoxy resin is 10:90 to
(Approximately 20:80). Next, the chip 1 was aligned and mounted. Next, using a thermocompression bonding head 5 provided with a projection 4 having a size of about 0.08 mm square and a height of about 0.08 mm at a position corresponding to the chip electrode, thermocompression bonding was performed from the flexible printed circuit board side to the chip side. As a result, the connection pad portion of the wiring pattern (conductor) 8 is deformed into a protruding shape, and a connection is made between the deformed protruding connection pad portion 14 and the chip electrode 15 by the conductive particles 10 and the epoxy resin 9 is cured. Will be implemented. The crimping temperature is about 200 ° C,
The time was about 20 seconds, and the pressure per unit area of the tip of the projection 4 was about 200 MPa. The connection resistance of the connection terminal was about 35 mΩ on average, and a sufficiently low resistance value was obtained.

Next, a second embodiment according to the present invention will be described with reference to FIGS.

In the second embodiment, when the wiring pattern 8 formed on the circuit board 2b is installed so as to enter the region where the anisotropic conductive film 3 is arranged, the connection pad of the wiring pattern is used. Forming a projection 11 made of a conductor on the portion, or forming a wiring pattern 8 formed on the circuit board 2c.
In the case where is installed so as not to enter the region where the anisotropic conductive film 3 is arranged, an independent connection pad portion 12 connected to the wiring pattern 8 through a lower layer is formed. FIG. 8 shows an embodiment in which a projection 11 made of a conductor is formed on a connection pad portion on a wiring pattern made of copper or the like formed on a circuit board 2b. FIG. 9 shows a cross-sectional shape when the bumpless semiconductor chip 1 is connected to the circuit board 2 b by heating and pressure bonding using the anisotropic conductive film 3. As shown in FIG. 9, by providing a projection 11 made of a conductor on the connection pad portion of the wiring pattern 8 on the circuit board 2 b, the conductive particles 10 other than between the chip electrode 15 and the projection 11 are pressed. Therefore, direct contact between the bumpless semiconductor chip 1 and the substrate 2b can be prevented.

By the way, since the formation of the projections 11 on the circuit board 2b can be performed at once before cutting into many pieces, the cost is extremely low as compared with the formation of bumps on a semiconductor chip. As the projection 11, a metal material such as copper or nickel, or a cured product of a conductive adhesive such as silver, gold, copper, or nickel is used.

Further, as shown in FIG. 10, in the multilayer printed circuit board 2c, wiring is performed from the inner wiring to the surface layer via via holes, and the independent wiring itself can be used as the connection pad portion (projection made of a conductor) 12. . In this method, a new step is not required for forming the independent connection pad portion (projection made of a conductor) 12. In this embodiment, when the wiring pattern 8 is formed on the surface of the multilayer printed circuit board 2c and the thickness of the connection pad portion (projection made of a conductor) 12 is made substantially the same as the thickness of the wiring pattern 8, a different The wiring pattern 8 is formed in the area where the isotropic conductive film 3 is set.
The conductive particles 10 are not pressurized except between the chip electrode 15 and the connection pad portion 12 so that the conductive particles 10 are not pressed between the chip electrode 15 and the connection pad portion 12. Pressurization enables connection with a low resistance value.

As described above, the anisotropic conductive film 3
In the flip-chip attach mounting according to the first embodiment, the protrusions 11 made of a conductor are provided on the connection pad portions of the circuit boards 2b and 2c.
By forming 2, further cost reduction can be realized.

The projections 11 made of a metal material on the connection pads of the circuit board 2b can be easily formed by a partial plating method in the printed wiring board manufacturing process. The protrusions 11 made of a cured product of the conductive adhesive are easily formed by supplying the conductive adhesive to the electrode pad portion by screen printing or microdispensing in a printed wiring board manufacturing process, and heating the electrode pad. Can be.

Another method of forming the projection 12 made of a metal material on the connection pad portion of the circuit board 2c is as shown in FIGS. 10 and 11, in the case of the multilayer printed wiring board 2c.
In this method, an independent connection pad portion 12 electrically connected to the inner layer through the through hole 13 is formed on the surface layer. This method has an advantage that a new process for forming a projection is not required.

The size of the projections 11 and 12 made of conductors provided on the connection pads of the circuit boards 2b and 2c may be slightly larger than the size of the electrode 15 of the semiconductor chip. Occurs.
Therefore, it is preferable that the size of the protrusions 11 and 12 is smaller than the size of the electrode 15 of the semiconductor chip. The height of the protrusions 11 and 12 made of a conductor is about 0.003 mm or more.
0.3 mm is preferred. When the height is about 0.003 mm or less, the semiconductor chip 1 and the circuit boards 2b and 2c are connected to the conductive particles 1 of the anisotropic conductive film 3 even at locations other than the electrode portions.
The problem of contact through 0 occurs. When the height of the projections 11 and 12 is 0.3 mm or more, it becomes difficult to form the projections in one process, and when the connection pitch is narrow, there is a problem that a short circuit occurs between adjacent pads. The shape of the protrusions 11 and 12 made of a conductor is not particularly limited to a circle, a square, or the like. As the circuit boards 2b and 2c used in the present invention, a rigid printed board, a flexible printed board, a ceramic board, a thin film board, or the like can be used, and is not particularly limited.

Next, the second embodiment described above will be described more specifically as an example.

[0054]

Embodiment 5 The following test chip was used as the bumpless semiconductor chip 1.

Size: 8 mm square Thickness: 0.45 mm Connection pad size: 0.105 × 105 mm Connection pad pitch: 0.13 mm Connection arrangement: 4 peripheral sides Six-layer glass epoxy board (FR4) as circuit board 2b
Then, a connection wiring (copper thickness: about 0.012 mm) 8 corresponding to the chip electrode 15 was formed. The width of the wiring was about 0.09 mm, and the interval between the wirings was about 0.04 mm.
The test chip and the wiring of the circuit board were designed so that the connection resistance could be measured by the four-terminal method.

A thermosetting conductive adhesive (Ag paste) pattern is formed on the connection terminals of the circuit board 2b by a screen printing method, and is cured at about 150 ° C. for 1 hour.
A projection 11 having a size of 8 mm square and a height of about 0.04 mm was formed.
Next, in the chip connection area of the circuit board 2b,
An anisotropic conductive film 3 made of gold-plated nickel conductive particles having a diameter of 0.008 mm and an uncured epoxy resin similar to that of No. 3 was bonded. Next, after the bumpless semiconductor chip 1 was aligned and mounted, the chip was pressed by a heating head. The pressing temperature was about 200 ° C., the pressure was about 6 kg, and the time was about 20 seconds. The connection resistance of the connection terminal was about 10 mΩ on average, and a sufficiently low resistance value was obtained.

[0057]

Embodiment 6 The same bumpless semiconductor chip 1 as in Embodiment 5 was used. Using a four-layer glass epoxy substrate (FR4) as the circuit board 2b, connection wiring (copper thickness: about 0.012 mm) 8 corresponding to the chip electrode 15 was formed. The width of the wiring is about 0.09 mm, and the interval between the wirings is about 0.1 mm.
04 mm. In the chip connection pad part of this board,
Further, a projection 11 of about 0.08 mm square and about 0.015 mm in height made of gold / nickel / copper was formed by plating.
Next, in the chip connection area of the circuit board 2b,
An anisotropic conductive film 3 made of gold-plated nickel conductive particles having a diameter of 0.008 mm and an uncured epoxy resin similar to that of No. 3 was bonded. Next, after the bumpless semiconductor chip 1 was aligned and mounted, the chip was pressed by a heating head. The pressing temperature was about 200 ° C., the pressure was about 6 kg, and the time was about 20 seconds. The connection resistance of the connection terminal was about 10 mΩ on average, and a sufficiently low resistance value was obtained.

[0058]

Embodiment 7 The same bumpless semiconductor chip 1 as that of Embodiment 5 was used. A four-layer glass epoxy substrate prepared by a transfer method was used as the circuit board 2b. The wiring width in the chip connection region is about 0.09 mm, and the wiring interval is about 0.5 mm.
04 mm. In the substrate formed by the transfer method, a protrusion 11 of about 0.08 mm square and about 0.025 mm in height made of gold / nickel is formed on the chip connection pad portion. Next, an anisotropic conductive film 3 made of gold-plated nickel conductive particles having a diameter of about 0.008 mm and an uncured epoxy resin similar to those in Examples 1 to 3 was provided in the chip connection area of the circuit board 2b.
Was pasted. Next, after the bumpless semiconductor chip 1 was aligned and mounted, the chip was pressed by a heating head. The pressing temperature was about 200 ° C., the pressure was about 6 kg, and the time was about 20 seconds. The connection resistance of the connection terminal was about 10 mΩ on average, and a sufficiently low resistance value was obtained.

[0059]

Embodiment 8 The same bumpless semiconductor chip 1 as that of Embodiment 5 was used. Using a six-layer ceramic substrate as the circuit substrate 2b, connection wirings corresponding to the chip electrodes were formed. Wiring width is about 0.09mm, wiring interval is about 0.04m
m. About 0.08 mm of gold / nickel / copper was further added to the chip connection pad portion of the surface wiring layer of this substrate.
A protrusion 11 having a corner and a height of about 0.015 mm was formed by plating. Next, an anisotropic conductive film 3 made of gold-plated nickel conductive particles having a diameter of about 0.008 mm and an uncured epoxy resin similar to those in Examples 1 to 3 was attached to the chip connection region of the circuit board. Next, after the bumpless semiconductor chip 1 was aligned and mounted, the chip was pressed by a heating head. The pressing temperature was about 200 ° C., the pressure was about 6 kg, and the time was about 20 seconds. Connection resistance of connection terminal is 10mΩ on average
And a sufficiently low resistance value was obtained.

[0060]

Embodiment 9 Bumpless semiconductor chip 1, circuit board 2b
Used the same members as in Example 5.

In the chip connection area of this circuit board 2b, anisotropically formed of conductive particles obtained by forming a gold film and a nickel film on the surface of plastic particles having a diameter of about 0.005 mm and an uncured epoxy resin as in Example 4 A conductive film was attached. Next, after the bumpless semiconductor chip 1 was aligned and mounted, the chip was pressed by a heating head. The pressing temperature was about 200 ° C., the pressure was about 6 kg, and the time was about 20 seconds. The connection resistance of the connection terminal was about 15 mΩ on average, and a sufficiently low resistance value was obtained.

[0062]

[Embodiment 10] The same chip as in Embodiment 5 was used as the bumpless semiconductor chip 1. A two-layer wiring flexible printed board was used as the circuit board 2b. Copper wiring thickness is about 0.03
5mm, wiring width in chip connection area is about 0.09m
m, and the wiring interval was about 0.04 mm. On the chip connection pad portion of this substrate, a protrusion 11 of about 0.06 mm square and about 0.012 mm in height made of gold / nickel / copper was further formed by plating. Next, an anisotropic conductive film 3 made of gold-plated nickel conductive particles having a diameter of about 0.008 mm and an uncured epoxy resin similar to those in Examples 1 to 3 was attached to the chip connection region of the circuit board. Next, after the bumpless semiconductor chip 1 was aligned and mounted, the chip was pressed by a heating head. The pressing temperature was about 200 ° C., the pressure was about 6 kg, and the time was about 20 seconds. The connection resistance of the connection terminal was about 10 mΩ on average, and a sufficiently low resistance value was obtained.

[0063]

Embodiment 11 The same chip as in Embodiment 5 was used as the bumpless semiconductor chip 1. A four-layer glass epoxy substrate (FR4) was used as the circuit board 2c, and the connection pad portions 12 corresponding to the chip electrodes 15 were routed from the inner layer through the through holes 13 (shown in FIGS. 10 and 11). The surface of the connection pad portion 12 was plated with nickel and gold. Next, an anisotropic conductive film 3 made of gold-plated nickel conductive particles having a diameter of about 0.008 mm and an uncured epoxy resin similar to those in Examples 1 to 3 was attached to the chip connection region of the circuit board. Next, after the bumpless semiconductor chip 1 was aligned and mounted, the chip was pressed by a heating head. The pressing temperature was about 200 ° C., the pressure was about 6 kg, and the time was about 20 seconds. The connection resistance of the connection terminal was about 10 mΩ on average, and a sufficiently low resistance value was obtained.

[0064]

According to the present invention, it is possible to realize a semiconductor bare chip mounting with extremely low cost and high reliability, which has a great industrial effect.

Further, according to the present invention, a bumpless semiconductor chip is connected to a circuit board with a low resistance without short-circuiting using an anisotropic conductive film, thereby realizing a very low cost and highly reliable semiconductor bare chip mounting. An effect that can be realized is achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a flip-chip attach mounting method for a bumpless press according to the present invention.

FIG. 2 is a cross-sectional view showing a semiconductor element mounting structure mounted by the mounting method shown in FIG.

FIG. 3 is a perspective view showing the thermocompression bonding head shown in FIG. 1;

FIG. 4 is an enlarged view showing an embodiment of a shape of a projection formed on a thermocompression bonding head.

FIG. 5 is an enlarged view showing another embodiment of a shape of a projection formed on a thermocompression bonding head.

FIG. 6 is a diagram showing a case where an anisotropic conductive film is attached to a bumpless semiconductor chip in the first embodiment shown in FIG.

FIG. 7 is a diagram showing a case where an anisotropic conductive film is attached to a flexi circuit board in the first embodiment shown in FIG.

FIG. 8 is a perspective view showing one embodiment of an independent connection pad portion formed on a circuit board for describing a second embodiment of the flip-chip attach mounting method of bumpless according to the present invention.

FIG. 9 is a cross-sectional view showing a semiconductor element mounting structure mounted using connection pad portions formed on the circuit board shown in FIG. 8;

FIG. 10 is a perspective view showing another embodiment of an independent connection pad portion formed on a circuit board for describing a second embodiment of the flip-chip attach mounting method of bumpless according to the present invention. .

11 is a cross-sectional view showing a semiconductor element mounting structure mounted using connection pad portions formed on the circuit board shown in FIG.

FIG. 12 is a diagram illustrating a bare chip mounting structure by a conventional wire bonding method.

FIG. 13 is a diagram showing a conventional bare chip mounting structure using gold bumps and solder.

FIG. 14 is a diagram showing a conventional bare chip mounting structure using gold bumps and a conductive adhesive.

FIG. 15 is a diagram showing a conventional bare chip mounting structure using gold bumps and an anisotropic conductive film.

FIG. 16 is a view showing a conventional method for assembling a bare chip mounting structure using gold bumps and an anisotropic conductive film.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Bumpless semiconductor chip, 2a ... Flexible printed board, 2b ... Circuit board, 2c ... Circuit board,
3 ... anisotropic conductive film, 4 ... protrusion, 5 ... thermocompression bonding head, 8 ... wiring pattern (conductor), 9 ... epoxy resin, 10 ... conductive particles, 11 ... protrusion made of conductor (connection pad portion), 12 ... Projection (connection pad),
13: Projecting connection pad portion, 15: Electrode

Claims (12)

[Claims] In a flip chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, the semiconductor element is formed by arranging a plurality of electrodes on which no bumps are formed. In the mounting surface region on the circuit board facing the semiconductor element, a plurality of projecting connection pad portions are arranged in parallel at positions facing the respective electrodes, and a space between the respective projecting connection pad portions and the respective electrodes is provided. A semiconductor element mounting structure, wherein the semiconductor element mounting structure is formed by connecting conductive particles inherent in the anisotropic conductive film. 2. A flip-chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, wherein the semiconductor element is formed by arranging a plurality of electrodes on which no bumps are formed. A plurality of connection pad portions are arranged in parallel at positions facing each other in the mounting surface region on the circuit board facing the semiconductor element by narrowing a gap with respect to each of the electrodes, and the difference between each connection pad portion and each of the electrodes is reduced. A semiconductor element mounting structure, wherein the semiconductor element mounting structure is formed by connecting conductive particles inherent in an isotropic conductive film. 3. A flip chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, wherein the semiconductor element is configured by arranging a plurality of electrodes on which no bumps are formed. In the mounting surface area on the circuit board facing the semiconductor element, a plurality of protruding connection pads connected to each of the plurality of wiring patterns are arranged in parallel at positions facing the respective electrodes, and each of the protruding connection pads is provided. A semiconductor element mounting structure, wherein a connection pad portion and each of the electrodes are connected by conductive particles inherent in the anisotropic conductive film. 4. A flip chip attach type semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, wherein the semiconductor element is configured by arranging a plurality of electrodes on which no bumps are formed. A plurality of connection pad portions connected to each of a plurality of wiring patterns in a mounting region on a circuit board opposed to the semiconductor element and protruded by locally deforming at a position facing each of the electrodes, A semiconductor element mounting structure, wherein each protruding connection pad portion and each of the electrodes are connected by conductive particles inherent in the anisotropic conductive film. 5. A flip-chip-attached semiconductor element mounting structure in which a semiconductor element is mounted on a circuit board with an anisotropic conductive film, wherein the semiconductor element is constituted by arranging a plurality of electrodes on which no bumps are formed. In the mounting area on the circuit board facing the semiconductor element, only a plurality of connection pad portions connected to the lower layer are arranged in parallel at positions facing the respective electrodes, and the difference between the respective connection pad portions and the respective electrodes is defined by the difference. A semiconductor element mounting structure, wherein the semiconductor element mounting structure is formed by connecting conductive particles inherent in an isotropic conductive film. 6. A semiconductor device in which a plurality of electrodes on which no bumps are formed are arranged in parallel, and a plurality of connection pads formed of a conductor deformed in a projecting shape on the side of the semiconductor device are arranged in parallel with each of the electrodes. A semiconductor element mounting structure, wherein the mounted circuit board is connected and bonded via an anisotropic conductive film. 7. An anisotropic conductive film adhering step of adhering an anisotropic conductive film to a flexible circuit board; A mounting step of mounting the semiconductor element in alignment with the provided semiconductor element, and a plurality of protrusions formed corresponding to the arrangement of the electrodes on the flexible circuit board mounted on the semiconductor element in the mounting step The conductor formed on the flexible circuit board is deformed into a protruding shape by pressing a heating head having a plurality of connection pad portions, and an anisotropic conductive path is formed between each of the connection pad portions and each of the electrodes. A heating head pressing step of connecting with conductive particles present in the film. 8. An anisotropic conductive film adhering step of adhering an anisotropic conductive film to a semiconductor element having a plurality of electrodes on which no bumps are formed, and attaching a flexible circuit board to the anisotropic conductive film. A mounting step of aligning and mounting with respect to the semiconductor element, and a plurality of protrusions formed corresponding to the arrangement of the respective electrodes on the flexible circuit board mounted on the semiconductor element in the mounting step. The conductor formed on the flexible circuit board is deformed into a projection shape by pressing a heating head having a plurality of connection pad portions, and an anisotropic conductive film is formed between each of the connection pad portions and each of the electrodes. And a heating head pressing step of connecting with conductive particles existing in the semiconductor device. 9. An anisotropic conductive film is used to connect and bond a semiconductor element having a plurality of electrodes on which no bumps are formed in parallel and a circuit board having a plurality of connection pads having projections made of conductors. A semiconductor element mounting structure characterized by comprising. 10. The semiconductor element mounting structure according to claim 9, wherein said projections made of a conductor are formed of a cured product of a conductive adhesive. 11. The semiconductor element mounting structure according to claim 9, wherein said projection made of a conductor is formed of a metal material. 12. A semiconductor device having a plurality of electrodes on which no bumps are formed and a circuit board having a plurality of connection pads formed on via holes are connected and bonded by an anisotropic conductive film. A semiconductor element mounting structure characterized by comprising.