HK1240399B - Bump-forming film, semiconductor device, manufacturing method thereof, and connection structure - Google Patents

Description

Bump formation film, semiconductor device, method for manufacturing the same, and connection structure

Technical Field

The present invention relates to a bump formation film for forming bumps on electrode pads of IC chips and the like.

Background Art

In order to achieve low on-resistance and stable on-reliability when flip-chip mounting a bumpless IC chip on a wiring substrate, a scheme has been proposed in which gold bumps are pre-set using a stud bumping method on the electrode pads of the bumpless IC chip that are not coated with a passivation film, and metal-bonded by ultrasonic heating to the metal-plated resin particles that are expected to function as bumps (Patent Document 1).

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Laid-Open No. 2005-286349.

Summary of the Invention

Problems to be solved by the invention

However, using the stud bumping method to provide gold bumps on the electrode pads of a bumpless IC chip significantly increases the manufacturing cost of the IC chip, making it difficult to commercially adopt the method. Furthermore, when ultrasonic heating is used to metal-bond the surface metal of the metal-coated resin particles to the electrode pads of a bumpless IC chip, there is the concern that the surface metal may peel off, significantly reducing the conduction reliability, and there is also the problem of a complicated manufacturing process.

An object of the present invention is to solve the above-mentioned problems of the prior art and to form bumps on semiconductor devices such as bumpless IC chips at low cost and with stable conduction reliability.

Solutions to Problems

The present inventors, under the assumption that the above-mentioned problem can be solved as long as a conductive filler that can be expected to function as a bump of a semiconductor device can be simply supplied to the electrode of a semiconductor device using a bump-forming film, found that the purpose of the present application can be achieved by regularly arranging the conductive filler for bumps in an insulating adhesive resin layer in periodic repeating units along the long side direction of the film when viewed from above, and by making a straight line connecting one end of the conductive filler for bumps in the thickness direction of the film approximately parallel to the surface of the film, thereby completing the present invention.

That is, the present invention provides "a film for forming bumps, in which conductive fillers for bumps are regularly arranged in an insulating adhesive resin layer when viewed from above, wherein the regular arrangement has periodic repeating units in the long side direction of the film, and a straight line connecting one end of the conductive filler for bumps in the thickness direction of the film is approximately parallel to the surface of the film."

The present invention also provides a method for producing the bump-forming film of the present invention, comprising the following steps (i) to (h):

＜Process（イ）＞

a step of preparing a transfer body having regularly arranged concave portions formed on its surface;

＜Process（ロ）＞

a step of filling the concave portions of the transfer body with a conductive filler for bumps; and

＜Process（ハ）＞

A step of laminating an insulating adhesive resin layer on the surface of the transfer member on the side where the conductive filler for bumps is to be filled and pressing the layer to transfer the conductive filler for bumps to the insulating adhesive resin layer.

Preferably, the manufacturing method further comprises the following step (ii):

＜Process (2)＞

A step of laminating an insulating adhesive cover layer from the side on which the conductive filler for bumps is transferred, onto the insulating adhesive resin layer to which the conductive filler for bumps is transferred.

Furthermore, the present invention provides an "electronic component having bumps arranged on a base electrode for bumps on its surface, wherein the bump-forming film is arranged on a base electrode-forming surface of the electronic component in such a manner that a conductive filler for bumps of the bump-forming film becomes the bumps of the base electrode." Specifically, the present invention provides a "semiconductor device having bumps arranged on a base electrode for bumps on its surface, wherein the bump-forming film is arranged on a base electrode-forming surface of the semiconductor device in such a manner that a conductive filler for bumps of the bump-forming film becomes the bumps of the base electrode."

Furthermore, the present invention provides a method for manufacturing an electronic component in which a base electrode for bumps on the surface is provided with bumps, wherein:

With respect to a bumpless electronic component having a base electrode for bumps on its surface, the base electrode is disposed on the base electrode-forming surface of the electronic component by placing the bump-forming film of the present invention so that the conductive filler for bumps is opposed to the base electrode, and then the conductive filler for bumps is fixed to the base electrode using an insulating adhesive resin constituting the bump-forming film. Specifically, a method for manufacturing a semiconductor device having bumps disposed on a base electrode for bumps on its surface is provided, wherein:

With respect to a bumpless semiconductor device having a base electrode for bumps on its surface, the base electrode is disposed on the base electrode formation surface of the semiconductor device in such a manner that the conductive filler for bumps of the bump-forming film of the present invention faces the base electrode, and then the conductive filler for bumps is fixed to the base electrode by curing the insulating adhesive resin layer constituting the bump-forming film.

Similarly, the present invention provides a method for manufacturing a semiconductor device having bumps arranged on a base electrode for bumps on the surface, wherein:

With respect to a bumpless semiconductor device having a base electrode for bumps on its surface, the base electrode is disposed on the base electrode of the semiconductor device by placing the bump-forming film of the present invention so that the conductive filler for bumps faces the base electrode, and then heating the conductive filler for bumps to allow metal bonding to the base electrode and fix the bumps.

Furthermore, the present invention provides a "connection structure, wherein the bumps of the base electrode arranged on the surface of the above-mentioned electronic component are connected to the corresponding terminals of the other electronic component by using a conductive filler via a curable or non-curable conductive adhesive or an insulating adhesive, or by forming a metallic bond between the two." Specifically, the present invention provides a "connection structure, wherein the bumps of the base electrode arranged on the surface of the above-mentioned semiconductor device are connected to the corresponding terminals of the other electrical component by using a conductive filler via a curable or non-curable conductive adhesive or an insulating adhesive, or by forming a metallic bond between the two."

Effects of the Invention

The bump-forming film of the present invention has a conductive filler for bumps regularly arranged in a periodically repeating unit along the long side of the film when viewed from above within the insulating adhesive resin layer. Therefore, the conductive filler for bumps can be arranged on each electrode of a semiconductor device such as an IC chip. Furthermore, in the bump-forming film of the present invention, a straight line connecting one end of the conductive filler for bumps in the thickness direction of the film is substantially parallel to the surface of the film. Therefore, even if there are some height variations on the electrodes that are to form bumps of the semiconductor device, the conductive filler for bumps can be stably arranged on them.

BRIEF DESCRIPTION OF THE DRAWINGS

[Fig. 1] Fig. 1 is a cross-sectional view of a bump-forming film according to the present invention.

[Fig. 2] Fig. 2 is a process diagram illustrating a method for manufacturing a bump-forming film according to the present invention.

[Figure 3] Figure 3 is a process diagram for explaining the method for manufacturing the bump-forming film of the present invention.

[Fig. 4] Fig. 4 is a process diagram illustrating a method for manufacturing a bump-forming film according to the present invention.

[Figure 5] Figure 5 is a process diagram illustrating the method for manufacturing the bump-forming film of the present invention.

[Fig. 6] Fig. 6 is a cross-sectional view of a semiconductor device according to the present invention.

[Fig. 7] Fig. 7 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 3 in which the conductive particles are arranged at a ratio of 1:5.

[Fig. 8] Fig. 8 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 10 in which the conductive particles are arranged in a ratio of 1:4.

[Fig. 9] Fig. 9 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 11 in which the conductive particles are arranged in a ratio of 1:16.

[Fig. 10] Fig. 10 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 12 in which the conductive particles are arranged in a ratio of 1:3.

[Figure 11] Figure 11 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 13 in which the conductive particles are arranged in a ratio of 1:9.

[Figure 12] Figure 12 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 14 in which the conductive particles are arranged in a ratio of 1:6.

[Figure 13] Figure 13 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 15 in which the conductive particles are arranged at a ratio of 1:20.

[Figure 14] Figure 14 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 16 in which the conductive particles are arranged in a ratio of 1:2.

[Figure 15] Figure 15 is a diagram showing the relationship between the conductive particles and the electrode pads in the bump formation film of Example 17 in which the conductive particles are arranged in a ratio of 1:8.

DETAILED DESCRIPTION

Hereinafter, the present invention will be described with reference to the accompanying drawings.

<Bump formation film>

As shown in Figure 1, the bump-forming film 10 of the present invention is a bump-forming film in which the conductive fillers 2 for bumps are regularly arranged in the insulating adhesive resin layer 1 when viewed from above. The regular arrangement of the conductive fillers 2 for bumps has a periodic repeating unit in the long side direction of the film. The periodic repeating unit can be appropriately selected according to the electrode pattern of the semiconductor device on which the bumps are to be formed. In addition, the number of conductive fillers 2 for bumps arranged at the electrodes of a semiconductor device on which the bumps are to be formed can be one or more than two. In addition, within the scope of not losing the effect of the invention, the conductive fillers 2 for bumps can be arranged close to each other or connected. When the conductive fillers 2 for bumps are arranged close to each other or connected, the influence of the configuration offset can be alleviated, and the alignment operation is easy.

In the bump-forming film 10 of the present invention, a straight line connecting one end of the conductive filler 2 for bumps in the thickness direction of the film is approximately parallel to the film surface. Figure 1 shows an example where the straight lines on the front and back sides of the film are parallel, respectively. This allows the conductive filler for bumps to be reliably and stably positioned on the electrodes of the semiconductor device where the bumps are to be formed. Furthermore, the degree of approximately parallelism means that the angle formed between the straight line connecting one end of the conductive filler 2 for bumps in the thickness direction of the film and the film surface is within ±5°.

As the conductive filler 2 for bumps, solder particles, nickel particles, metal-coated resin particles, etc. can be cited. Among them, solder particles and solder-plated resin particles that can be metal-bonded with terminal materials such as copper at relatively low temperatures can be preferably cited. In particular, solder particles are preferred. In addition, from the viewpoint of easily obtaining the conduction reliability of the connection between the bump electrode and the terminals of other electronic components corresponding thereto, metal-coated resin particles can be preferably used. Here, the metal coating of the metal-coated resin particles can be formed using a known metal film forming method such as an electroless plating method or a sputtering method. In addition, in order to improve the conduction reliability, the core resin particles constituting the metal-coated resin particles can be made to contain conductive particles.

The average particle diameter of the conductive bump filler 2, as measured using an imaging-based particle size distribution analyzer, is preferably 3 to 60 μm, more preferably 8 to 50 μm. This range facilitates conformity to the terminal dimensions of typical semiconductor devices. Furthermore, to ensure consistent pressure on each terminal, the size (average particle diameter) of the conductive bump filler 2 is preferably approximately uniform. "Approximately uniform" here means that the ratio of the particle diameter to the standard deviation of the average particle diameter, or CV value, is 20% or less, preferably 10% or less.

The conductive filler 2 for bumps is preferably spherical, but may also be a roughly spherical or ellipsoidal shape. Furthermore, the surface may have fine irregularities. The presence of fine irregularities can increase the surface area and provide an anchoring effect when pressed, thereby reducing or stabilizing the resistance during conduction.

On the other hand, the thickness of the insulating adhesive resin layer 1 is preferably 0.5 to 20 times the average particle diameter of the conductive filler 2 for bumps, and more preferably 0.8 to 15 times. Within this range, the bumps can be stably fixed. Furthermore, within this range, the thickness of the insulating adhesive resin layer 1 is preferably set so that a portion of the conductive filler 2 for bumps is exposed. This improves ease of handling, such as removal of the insulating adhesive resin layer 1 and lamination with other insulating adhesive resin layers, as described later.

In order to secure the conductive filler 2 for bumps to the semiconductor device electrode, the insulating adhesive resin layer 1 preferably has adhesive properties. However, to improve adhesion, it may also be photocurable or thermosetting. Once the insulating adhesive resin layer 1 is cured, the conductive filler 2 for bumps and the semiconductor device electrode form a metallic bond. The insulating adhesive resin layer 1 can then be removed, leaving the metallically bonded conductive filler 2 for bumps.

Alternatively, when the conductive bump filler 2 is secured with the insulating adhesive resin layer 1 without metallic bonding, it can be bonded to other electronic components simultaneously with another insulating adhesive resin layer. In this case, the additional insulating adhesive resin layer can be pre-installed on the other electronic components or laminated on the insulating adhesive resin layer containing the conductive bump filler 2. In this case, if the conductive bump filler 2 is composed of metal-plated resin particles, the particle diameter can be larger than the total thickness of the insulating adhesive resin layer. This is because the rebound of the resin particles after deformation (flattening) due to bonding facilitates maintaining electrical continuity. If the conductive bump filler 2 is made of a material that flattens easily, it is preferable to slightly separate the conductive bump fillers 2 from each other to avoid hindering flattening. This is because there is a concern that the conductive bump fillers 2 may shift in position due to flattening. As an example, the separation is preferably at least 20% of the size (average particle diameter) of the conductive bump filler 2, and more preferably at least 30%. On the other hand, if the separation is greater than 50%, there is a concern that the capture efficiency will decrease, so it is preferably less than 50%. This allows the conductive filler for the bump to be densely distributed in the required locations, which is preferable from the perspective of ensuring quality during manufacturing (and also from the perspective of stabilizing the on-resistance value).

When the conductive fillers 2 for bumps are separated from each other at such a level, a unit cell may be formed from a plurality of conductive fillers for bumps 2. Forming a unit cell is preferred because it stabilizes the on-resistance value.

In addition, the outer shape of such a unit is preferably rectangular or circular because the general shape of the bump itself is such a shape.

When the cells are rectangular, the required height and width (i.e., aspect ratio) of the bumps will be determined. However, the size (average particle diameter) of the conductive filler 2 for the bumps should be equivalent to the required height. The width can be determined by forming the conductive filler 2 for the bumps into cells in rows along the width. In this case, the aforementioned spacing is also preferred. Alternatively, the rows may be offset by half the average particle diameter of the conductive filler 2 for the bumps.

In addition, when the unit is circular, it can also be a shape in which one bump conductive filler 2 is the center and other bump conductive fillers 2 are arranged in a circular shape along its periphery. In this case, it is also preferable to maintain the above-mentioned distance interval. The shape can also be a shape in which conductive particles are arranged at each corner and center of a regular polygon such as an equilateral triangle or a square. In addition, the shape of the regular polygon can also be deformed. This is to make the pressing by the tool uniform when there are multiple bump forming parts on the same surface.

To make the insulating adhesive resin layer 1 photocurable or thermosetting, the resin composition comprising the insulating adhesive resin layer 1 can be blended with not only known photocurable or thermocurable oligomers or monomers but also a photopolymerization initiator or thermopolymerization initiator. Suitable insulating adhesive resin layers include thermoplastic acrylic or epoxy resin films, thermosetting or photocurable acrylic or epoxy resin films, and the like. The thickness of such insulating adhesive resin layers 1 is typically 10 to 40 μm.

<Method for Manufacturing Bump-Forming Film>

The bump-forming film of the present invention can be produced by the following steps (i) to (h), preferably by a production method including step (ii). Each step will be described in detail with reference to the accompanying drawings.

(Process (i))

First, as shown in Figure 2, a transfer member 100 is prepared, having regularly arranged recesses 50 (e.g., columnar recesses corresponding to the grid points of a planar lattice pattern) formed on its surface. The depth of recesses 50 can be determined based on the electrode pitch, electrode width, inter-electrode spacing width, and average particle diameter of the conductive filler used for the bumps, etc., of the electrodes (electrode pads, through-holes, vias, etc.) of the semiconductor device, such as the IC chip, on which the bumps are to be formed.

＊Specific examples of transfer media

The transfer body to be prepared in step (i) can be produced using known methods. For example, a metal plate can be processed to form a master, which can then be coated with a curable resin and cured. Specifically, a flat metal plate is cut to form a transfer body master having protrusions corresponding to the concave portions. The resin composition constituting the transfer body is then applied to the surface of the master forming the protrusions, cured, and then pulled away from the master to obtain the transfer body.

(Process(ロ))

3, the concave portions 50 of the transfer body 100 are filled with the conductive filler 2 for bumps. Specifically, the conductive filler 2 for bumps is spread from above the concave portions 50 of the transfer body 100, and the unfilled filler is removed with a brush, a scraper, or an air blower.

(Process (ハ))

Next, as shown in FIG4 , an insulating adhesive resin layer 1 is placed on the surface of the transfer member 100 on the side filled with the conductive filler 2 for bumps and pressed, thereby transferring the conductive filler 2 for bumps to one side of the insulating adhesive resin layer 1. In this case, the conductive filler 2 for bumps can be buried in the insulating adhesive resin layer 1. Thus, the bump-forming film 10 shown in FIG1 is obtained.

Furthermore, the bump-forming film of the present invention can be obtained through the above steps (i) to (h), but the following step (ii) may be further performed.

(Process (2))

As shown in FIG5 , an insulating adhesive cover layer 6 can be laminated on the insulating adhesive resin layer 1 to which the conductive bump filler 2 is transferred, from the side on which the conductive bump filler is transferred. This provides a bump-forming film 20 having a two-layer structure of insulating adhesive resin layers. The insulating adhesive cover layer 6 can be made of the same material as the insulating adhesive resin layer 1, but adhesive resin films, thermosetting resin films, and photocurable resin films can also be used.

(Electronic components such as semiconductor devices)

The bump-forming film of the present invention can be used to form bumps on electrodes of electronic components. Specifically, the electronic component has a structure in which bumps are arranged on a base electrode for bumps on its surface, so that the bump-forming conductive filler of the bump-forming film serves as the bumps of the base electrode. The bump-forming film is disposed on the surface of the electronic component where the base electrode is formed. Specifically, the bump-forming film of the present invention is preferably used to form bumps on electrodes (pads, through-holes, via holes, etc.) of semiconductor devices such as IC chips and semiconductor wafers. When used on through-holes or via holes, the bumps can be embedded in the holes. When used on electrode pads, for example, as shown in FIG6 , a semiconductor device 200 has a structure in which bumps are arranged on a base electrode 60 for bumps surrounded by a passivation film 30. The bump-forming filler 2 of the bump-forming film 10 of the present invention serves as the bumps of the base electrode 60. The bump-forming film 10 is disposed on the surface of the semiconductor device 200 where the base electrode is formed. This semiconductor device is also an embodiment of the present invention.

Generally, the conductive filler for the bump is fixed to the base electrode by a curable or non-curable insulating adhesive resin constituting the bump forming film, but in the method of Figure 6, it is preferred to fix the conductive filler 2 for the bump to the base electrode 60 by curing the insulating adhesive resin layer 1 constituting the bump forming film 10.

Alternatively, the bump-forming filler 2 may be heated by resistance heating, ultrasonic heating, or the like to be metal-bonded to the base electrode 60, thereby fixing the bump-forming conductive filler 2 to the base electrode 60. In this case, after the metal bond is formed, the insulating adhesive resin layer 1 constituting the bump-forming film 10 may be cured and then peeled off.

(Method for manufacturing electronic components such as semiconductor devices)

An electronic component having bumps arranged on a base electrode for bumps on its surface can be manufactured by the following manufacturing method: after placing a bump-forming film of the present invention on the surface of a bumpless electronic component having a base electrode for bumps on its surface so that the conductive filler for bumps of the bump-forming film faces the base electrode, the bump-forming film is placed on the surface of the electronic component where the base electrode is to be formed, and then the conductive filler for bumps is fixed to the base electrode using an insulating adhesive resin constituting the bump-forming film. Specifically, a semiconductor device of the present invention having bumps arranged on the surface of a base electrode for bumps can be manufactured by the following manufacturing method: after placing a bump-forming film of the present invention on the surface of a bumpless semiconductor device having a base electrode for bumps on its surface so that the conductive filler for bumps of the bump-forming film faces the base electrode, the bump-forming film is placed on the surface of the semiconductor device where the base electrode is to be formed, and then curing the insulating adhesive resin layer constituting the bump-forming film by heating or light irradiation to fix the conductive filler for bumps to the base electrode.

Furthermore, the semiconductor device of the present invention having bumps disposed on a base electrode for bumps on its surface can also be manufactured by the following manufacturing method: a bumpless semiconductor device having a base electrode for bumps on its surface is provided with the base electrode, the bump-forming film of the present invention is disposed on the base electrode-forming surface of the semiconductor device so that the base electrode faces the bump-forming filler, and then the bump-forming filler is heated to be metal-bonded to the base electrode and fixed. These manufacturing methods are also one embodiment of the present invention.

(Connecting structure)

The bumps of the base electrode disposed on the surface of the electronic component of the present invention are connected to the corresponding terminals of other electronic components using a conductive filler via a curable or non-curable conductive adhesive or an insulating adhesive, or by forming a metal bond between the two to obtain a connection structure. Specifically, the bumps of the base electrode disposed on the surface of the semiconductor device of the present invention are connected to the corresponding terminals of other electronic components using a conductive filler via a curable or non-curable conductive adhesive or an insulating adhesive, or by forming a metal bond between the two to obtain a connection structure. These connection structures are also one embodiment of the present invention.

Example

Hereinafter, the present invention will be described in detail with reference to examples.

Example 1

A 2mm thick nickel plate was prepared and cylindrical protrusions (35μm outer diameter, 30μm height) were formed as a transfer master. 280 protrusions were arranged around a 7mm square with a 200μm inner periphery, at a density of 5.7 protrusions/ ^mm2 .

A photopolymerizable resin composition containing 60 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.), 29 parts by mass of an acrylic resin (M208, Toagosei Co., Ltd.), and 2 parts by mass of a photopolymerization initiator (IRGACURE 184, BASF Japan Co., Ltd.) was applied to the resulting transfer master so that the dry thickness became 30 μm. After drying at 80°C for 5 minutes, the composition was irradiated with 1000 mJ of light using a high-pressure mercury lamp to produce a transfer body.

On the surface of the transfer body peeled from the transfer body master, solder particles with an average particle diameter of 30 μm (fine solder powder, Mitsui Mining & Smelting Co., Ltd.) were dispersed as a conductive filler as bumps, and then the solder particles were filled into the recesses by air blowing.

A 20μm-thick insulating adhesive resin film formed on a PET film was placed on the solder particle-filled surface of the transfer body. Pressing was performed at 50°C and 0.5 MPa, transferring the solder particles while embedding them in the insulating adhesive resin film. The conductive particles were arranged in a 1:1 pattern (one conductive particle per electrode pad). This yielded a bump-forming film with a total thickness of 30μm. Furthermore, one end of the conductive particle in this bump-forming film was approximately aligned with the film interface.

The insulating adhesive resin film used in Example 1 was prepared by preparing a mixed solution containing 60 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.), 40 parts by mass of an epoxy resin (jER828, Mitsubishi Chemical Co., Ltd.), and 2 parts by mass of a cationic curing agent (SI-60L, Sanshin Chemical Co., Ltd.). The mixed solution was then applied to a PET film having a film thickness of 50 μm and dried in an oven at 80°C for 5 minutes.

Example 2

A transfer body was prepared by repeating the same procedures as in Example 1, except that a transfer body master was used in which the outer diameter of the protrusions was changed to 25 μm and the height was changed to 20 μm. Solder particles (fine solder powder, Mitsui Mining & Smelting Co., Ltd.) having an average particle diameter of 20 μm were dispersed in the transfer body, and then the solder particles were filled into the concave portions by air blowing.

An insulating adhesive resin film was applied to both sides of the transfer body filled with solder particles in the same manner as in Example 1, thereby obtaining a bump-forming film having a total thickness of 30 μm. Furthermore, in this bump-forming film, one end of the conductive particles was substantially aligned with the film interface, as in Example 1.

Example 3

The bump-forming film was obtained by repeating the same procedures as in Example 2, except that the average density of the bumps on the transfer master was 28.5 per ^mm² and the arrangement pattern of the conductive particles was a 1:5 arrangement as shown in FIG7. In this example, a 1:5 arrangement was adopted, and when the film was viewed from above, the electrode pad P to be transferred and a total of five conductive particles 2 were arranged adjacent to the electrode pad P.

Comparative Example 1

The same operation as in Example 1 was repeated except that a transfer master in which convex portions were randomly arranged (convex portion density: 60 pcs/mm ² ) was used to obtain a bump-forming film.

Examples 4 to 6 and Comparative Example 2

The same procedures as in Examples 1 to 3 and Comparative Example 1 were repeated, except that a 30 μm thick insulating adhesive resin film formed on a PET film was placed as an insulating adhesive resin film suitable for the solder particle filling surface of the transfer body. The film was pressed at a temperature of 50°C and a pressure of 0.5 MPa, thereby transferring the solder particles while embedding them into the insulating adhesive resin film. Thus, each bump formation film having a total thickness of 30 μm was obtained. Furthermore, in each of these bump formation films, as in Example 1, one end of the conductive particles was substantially aligned with the film interface.

The insulating adhesive resin films used in Examples 4 to 6 and Comparative Example 2 were prepared by preparing a mixed solution containing 30 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.), 60 parts by mass of an acrylic monomer (LIGHT ACRYLATE 3EGA, Kyoeisha Chemical Co., Ltd.), and 3 parts by mass of a photoradical polymerization initiator (IRGACURE 184, BASF Japan Co., Ltd.). The mixed solution was then applied onto a 50 μm thick PET film and dried in an 80°C oven for 5 minutes.

Examples 7 to 9 and Comparative Example 3

The same procedures as in Examples 1 to 3 and Comparative Example 1 were repeated, except that a 30 μm thick insulating adhesive resin film formed on a PET film was placed as an insulating adhesive resin film suitable for the solder particle filling surface of the transfer body. The film was pressed at a temperature of 50°C and a pressure of 0.5 MPa, thereby transferring the solder particles while embedding them into the insulating adhesive resin film. Thus, each bump formation film having a total thickness of 30 μm was obtained. Furthermore, in each of these bump formation films, as in Example 1, one end of the conductive particles was substantially aligned with the film interface.

The insulating adhesive resin films used in Examples 7 to 9 and Comparative Example 3 were prepared by preparing a mixed solution containing 30 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.), 60 parts by mass of an acrylic monomer (LIGHT ACRYLATE 3EGA, Kyoeisha Chemical Co., Ltd.), 3 parts by mass of a release agent (BYK3500, BYK-CHEMIE JAPAN Co., Ltd.), and 3 parts by mass of a photoradical polymerization initiator (IRGACURE 184, BASF JAPAN Co., Ltd.). The mixed solution was then applied onto a PET film having a film thickness of 50 μm and dried in an oven at 80°C for 5 minutes.

(evaluate)

Using the bump formation films of Examples 1 to 9 and Comparative Examples 1 to 3, connection structures were fabricated as described below. The on-resistance values during bump formation (initial on-resistance) and the on-resistance values after applying a 50V voltage in an environment of 85°C and 85% humidity (resistance after a high-temperature, high-humidity bias test) were measured and evaluated. The on-resistance values were measured using a digital multimeter (34401A, Agilent Technologies) using the four-terminal method with a current of 1 mA.

For the initial on-resistance, values below 5Ω were considered good (G), and values above this were considered bad (NG). Furthermore, for the on-resistance after the high-temperature, high-humidity bias test, values below 20Ω were considered good (G), and values above this were considered bad (NG). The results are shown in Table 1.

(Fabrication of Connected Structures Using the Bump Forming Films of Examples 1 to 3 and Comparative Example 1)

A bump-free IC chip (size: 7mm vertical x 7mm horizontal x 200μm thick) with peripherally arranged aluminum electrode pads (30μm diameter, 85μm pitch, 280 pins) was bonded to the electrode pads using a bump-forming film. The film was then pressed at 50°C and 0.5MPa to secure the pads. In Examples 1 and 2, each electrode pad was assigned a conductive filler (solder particles). The IC chip, with the bump-forming film bonded to it, was then bonded to an epoxy glass substrate (material: FR4) for IC mounting at 180°C, 40MPa, and a heat-pressing time of 10 seconds. This resulted in a bonded structure.

(Fabrication of Connected Structures Using the Bump Forming Films of Examples 4 to 6 and Comparative Example 2)

As in Example 1, the bump-forming film was attached to the IC chip and then irradiated with ultraviolet light at a wavelength of 365 nm (irradiation intensity 100 mW, irradiation dose 2000 mW/ ^cm² ) for photoradical polymerization, thereby securing the chip. In Examples 3 and 4, the conductive filler (solder particles) for each bump was assigned to each electrode pad. The IC chip, with the bump-forming film attached, was then connected to an epoxy glass substrate (material: FR4) for IC mounting via a cationic polymerizable insulating adhesive resin film (composed of 60 parts by mass of a phenoxy resin (YP-50, Nippon Steel & Sumikin Chemical Co., Ltd.), 40 parts by mass of an epoxy resin (jER828, Mitsubishi Chemical Co., Ltd.), and 2 parts by mass of a cationic curing agent (SI-60L, Sanshin Chemical Co., Ltd.) at 180°C, a pressure of 40 MPa, and a heating and pressing time of 20 seconds. This resulted in a connected structure.

(Fabrication of Connected Structures Using the Bump Forming Films of Examples 7 to 9 and Comparative Example 3)

As in Example 1, the bump-forming film was attached to the IC chip and then irradiated with ultraviolet light at a wavelength of 365 nm (irradiation intensity 100 mW, irradiation dose 2000 mW/ ^cm² ) for photoradical polymerization, thereby securing the chip. In Examples 5 and 6, one conductive bump filler (solder particles) was applied to each electrode pad. The bump-forming film was then peeled from the IC chip, and the conductive bump filler was bonded to the electrode pads of the IC chip. The IC chip in this state was then bonded to an epoxy glass substrate (material: FR4) for IC mounting under the conditions of a temperature of 180°C, a pressure of 40 MPa, and a heating and pressing period of 20 seconds. This resulted in a bonded structure.

[Table 1]

As can be seen from Table 1, the bump-forming films of Examples 1 to 9 can be configured with conductive fillers that function as bumps on the electrode pads of the bumpless IC chip, and the evaluations of "initial on-resistance" and "on-resistance after high-temperature and high-humidity bias test" are good. In addition, no short circuit occurs. In particular, in the case of the bump-forming films of Examples 3, 6, and 9, the number of conductive fillers present in and near one electrode pad of the bumpless IC chip is 5. Therefore, when manufacturing the connection structure, the alignment accuracy between the bump-forming film and the electrode pad of the bumpless IC chip can be improved. In contrast, the bump-forming films of Comparative Examples 1 to 3 were evaluated as poor in both "initial on-resistance" and "on-resistance after high-temperature and high-humidity bias test." A short circuit also occurred.

Example 10

The same procedures as in Example 1 were repeated, except that the outer diameter of the protrusions on the transfer master was changed to 12 μm and the height was 10 μm. The arrangement of the conductive particles was changed to a 1:4 arrangement as shown in Figure 8. Furthermore, the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 10 μm. The thickness of the insulating adhesive resin film was changed to 8 μm. A bump-forming film with a total thickness of 10 μm was obtained. The density of the protrusions on the transfer master was 22.9/ ^mm² . Furthermore, the closest distance between the protrusions was 4.9 μm.

Example 11

By repeating the same procedures as in Example 1, except that the bumps on the transfer master were changed to an outer diameter of 12 μm and a height of 10 μm, the arrangement of the conductive particles was changed to a 1:16 arrangement as shown in Figure 9, and the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 10 μm, a bump-forming film with a total thickness of 10 μm was obtained. This ensured that the conductive filler for the bumps was also present around the periphery of the bumps, thereby widening the allowable range of misalignment during the film bonding process. The density of the bumps on the transfer master was 91.4/ ^mm² . Furthermore, the closest distance between the bumps was 4.9 μm.

Example 12

The same procedures as in Example 1 were repeated, except that the outer diameter of the protrusions on the transfer master was changed to 12 μm and the height was 10 μm. The arrangement of the conductive particles was changed to a 1:3 arrangement as shown in Figure 10. Furthermore, the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 10 μm. A bump-forming film with a total thickness of 10 μm was obtained. The density of the protrusions on the transfer master was 17.1/ ^mm² . The closest distance between the protrusions was 4.9 μm.

Example 13

By repeating the same procedures as in Example 1, except that the bumps on the transfer master were changed to have an outer diameter of 12 μm and a height of 10 μm, the arrangement of the conductive particles was changed to a 1:9 arrangement as shown in Figure 11, and the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 10 μm, a bump-forming film with a total thickness of 10 μm was obtained. By including the conductive filler for the bumps around the periphery of the bumps, the permissible range of misalignment during the film bonding process can be expanded. The density of the bumps on the transfer master was 51.4/ ^mm² . Furthermore, the closest distance between the bumps was 4.9 μm.

Example 14

The same procedures as in Example 1 were repeated, except that the outer diameter of the protrusions on the transfer master was changed to 12 μm and the height was 10 μm. The arrangement of the conductive particles was changed to a 1:6 arrangement as shown in Figure 12. Furthermore, the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 10 μm. A bump-forming film with a total thickness of 30 μm was obtained. The density of the protrusions on the transfer master was 34.3/ ^mm² . Furthermore, the closest distance between the protrusions was 4.9 μm.

Example 15

By repeating the same procedures as in Example 1, except that the bumps on the transfer master were changed to have an outer diameter of 12 μm and a height of 10 μm, the arrangement of the conductive particles was changed to a 1:20 arrangement as shown in Figure 13, and the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 10 μm, a bump-forming film with a total thickness of 10 μm was obtained. By including the conductive filler for the bumps around the periphery of the bumps, the permissible range of misalignment during the film bonding process can be expanded. The density of the bumps on the transfer master was 114.3/ ^mm² . Furthermore, the closest distance between the bumps was 4.9 μm.

Example 16

The same procedures as in Example 1 were repeated, except that the outer diameter of the protrusions on the transfer master was changed to 24 μm and the height was 20 μm. The arrangement of the conductive particles was changed to a 1:2 arrangement as shown in Figure 14. Furthermore, the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 20 μm. The thickness of the insulating adhesive resin film was changed to 16 μm. A bump-forming film with a total thickness of 20 μm was obtained. The density of the protrusions on the transfer master was 11.4/ ^mm² . Furthermore, the closest distance between the protrusions was 9.9 μm.

Example 17

By repeating the same procedures as in Example 1, except that the bumps on the transfer master were changed to an outer diameter of 24 μm and a height of 20 μm, the arrangement of the conductive particles was changed to a 1:8 arrangement as shown in Figure 15, and the conductive filler for the bumps was changed to gold/nickel-coated resin particles (MICRO PEARL, Sekisui Chemical Co., Ltd.) with an average particle diameter of 20 μm, a bump-forming film with a total thickness of 20 μm was obtained. By including the conductive filler for the bumps around the periphery of the bumps, the permissible range of misalignment during the film bonding process can be expanded. The density of the bumps on the transfer master was 45.71/ ^mm² . Furthermore, the closest distance between the bumps was 9.9 μm.

(Fabrication of Connected Structures Using the Bump Forming Films of Examples 10 to 17)

A connection structure similar to that of Example 1 was produced except that the bump formation films of Examples 10 to 15 were used. Furthermore, in the case of the bump formation films of Examples 16 and 17, the aluminum electrode pads disposed on the periphery to be evaluated were changed to 30 μm in length by 85 μm in width, with an 85 μm pitch (55 μm between pads) and 280 terminals. Connection structures were produced in the same manner as in Example 1 except that the pads had a length of 30 μm and a width of 85 μm, and a spacing of 85 μm (55 μm between pads).

The initial on-resistance of the connection structures produced in Examples 10 to 17 was evaluated in the same manner as in Example 1. All were found to be below 5Ω, confirming no practical problems. Furthermore, after 500 hours of conduction reliability testing in an 85°C/85% ambient temperature environment, all showed on-resistance values below 20Ω after a high-temperature, high-humidity bias test, confirming no practical problems. Furthermore, no short circuits occurred in any of the structures.

Furthermore, bump-forming films and connection structures were produced by repeating the same procedures as in Examples 10 to 17, except that the thickness of the resin films of Examples 10 to 15 was changed to 20 μm, and the thickness of the resin films of Examples 16 and 17 was changed to 25 μm, and that the conductive particles were pressed into one surface of the film to bury the conductive particles. These films were evaluated in the same manner as in Examples 10 to 17, and similarly good results were obtained as in Examples 10 to 17.

Industrial applicability

The bump-forming film of the present invention is useful when mounting a bumpless IC chip or the like on a wiring substrate.

Label Description

1 Insulating adhesive resin layer; 2 Conductive filler for bumps; 6 Insulating adhesive cover layer; 10, 20 Bump formation films; 30 Passivation film; 50 Concave portion of transfer body; 60 Base electrode; 100 Transfer body; 200 Semiconductor device; P-electrode pad.

Claims (26)

1. A bump-forming film, wherein, when viewed from above, bumps are regularly arranged in a conductive filler within an insulating adhesive resin layer, wherein the bump-forming film is a single layer, the regularly arranged bumps have periodic repeating units along the long side of the film, and a straight line connecting one end of the conductive filler of the bumps in the thickness direction of the film is parallel to the surface of the film. The insulating adhesive resin layer is either photocurable or thermocurable. 2. The bump forming film as claimed in claim 1, wherein a plurality of bumps are formed by conductive fillers in a unit, and the shortest distance between the conductive fillers in the bumps within the unit is less than 50% of the average particle diameter of the conductive fillers in the bumps. 3. The bump forming film as claimed in claim 2, wherein the unit of the bump filled with conductive filler is circular in shape. 4. The bump forming film as claimed in claim 2, wherein the bump is provided with conductive filler at each corner and center of the regular polygon. 5. The film for forming bumps as claimed in claim 2, wherein the units of the conductive filler for the bumps are disposed at each corner and center of the polygon that deforms the regular polygon. 6. The bump-forming film as claimed in claim 1, wherein the average particle diameter of the conductive filler for the bumps is the same. 7. The film for forming bumps as claimed in claim 1, wherein the conductive filler for the bumps is metal-coated resin particles. 8. The bump forming film as claimed in claim 1, wherein the conductive filler for the bumps is solder particles. 9. The film for forming bumps as claimed in claim 1, wherein the average particle diameter of the conductive filler for the bumps is 3 to 60 μm, and the thickness of the insulating adhesive resin layer is 0.5 to 20 times the average particle diameter. 10. The bump-forming film as claimed in claim 1, wherein a portion of the conductive filler for the bumps is exposed from the insulating adhesive resin layer. 11. A method for manufacturing a bump-forming film according to claim 1, comprising the following steps (A) to (C): <Process (A)> The process of preparing a transfer body with regularly arranged recesses on the surface; <Process (B)> The process of filling the recesses of the transfer body with conductive filler to create raised dots; and <Process (C)> The process of overlapping an insulating adhesive resin layer on the surface of the conductive filler side of the filling bump of the transfer body and pressing it, thereby transferring the conductive filler of the bump to the insulating adhesive resin layer. 12. The manufacturing method of claim 11, further comprising the following step (D): <Process (D)> For an insulating adhesive resin layer with a conductive filler for protrusion, the process of laminating an insulating adhesive capping layer from the side where the conductive filler for protrusion is transferred. 13. An electronic component having bumps disposed on a substrate electrode for bumps on its surface, wherein the bump forming film is disposed on the substrate electrode forming surface of the electronic component in such a way that the bumps of the bump forming film according to any one of claims 1 to 10 are made into bumps of the substrate electrode by means of a conductive filler. 14. A semiconductor device having bumps disposed on a substrate electrode for bumping on a surface, wherein the bump forming film is disposed on the substrate electrode forming surface of the semiconductor device in such a way that the bumps of the bump forming film according to any one of claims 1 to 10 are made into bumps of the substrate electrode by means of a conductive filler. 15. The semiconductor device of claim 14, wherein the bumps are fixed to the substrate electrode by a conductive filler by curing the insulating adhesive resin layer constituting the bump forming film. 16. The semiconductor device of claim 14, wherein the conductive filler for the bump is fixed to the base electrode by heating to metal bond the conductive filler for the bump to the base electrode. 17. The semiconductor device of claim 16, wherein, after the metal bond is formed, the insulating adhesive resin layer constituting the bump-forming film is peeled off after curing. 18. A method for manufacturing an electronic component, wherein the electronic component has bumps on a substrate electrode for use with bumps on its surface, wherein, For a base electrode of a bumpless electronic component having a base electrode with bumps on its surface, after the bump forming film is disposed on the base electrode forming surface of the electronic component in such a manner that the bump forming conductive filler of the bump forming film according to any one of claims 1 to 10 is facing the base electrode, the bump forming film is fixed to the base electrode using an insulating adhesive resin constituting the bump forming film. 19. A method for manufacturing a semiconductor device, wherein bumps are disposed on a substrate electrode for bumps on the surface of the semiconductor device, wherein... For the base electrode of a bumpless semiconductor device having a base electrode for bumping on its surface, after the bump forming film is disposed on the base electrode forming surface of the semiconductor device such that the bump forming film of any one of claims 1 to 10 is opposite to the base electrode, the bump forming film is fixed to the base electrode by curing the insulating adhesive resin layer constituting the bump forming film. 20. A method for manufacturing a semiconductor device, wherein bumps are disposed on a substrate electrode for bumps on the surface of the semiconductor device, wherein... For the base electrode of a bumpless semiconductor device having a base electrode with bumps on its surface, after the bump forming film is disposed on the base electrode forming surface of the semiconductor device in such a manner that the bump forming conductive filler of the bump forming film according to any one of claims 1 to 10 is placed opposite the base electrode, the bump forming film is fixed by metal bonding to the base electrode by heating the bump conductive filler. 21. A connection structure wherein the bumps of the base electrode disposed on the surface of the electronic component of claim 13 are connected by a conductive filler and corresponding terminals of other electronic components via a curable or non-curable conductive adhesive or an insulating adhesive, or by forming a metallic bond between the two. 22. A connection structure wherein bumps of a base electrode disposed on the surface of a semiconductor device according to any one of claims 14 to 17 are connected by a conductive filler and corresponding terminals of other electrical components via a curable or non-curable conductive adhesive or insulating adhesive, or by forming a metallic bond between the two. 23. An electronic component having bumps disposed on a base electrode for bumping on its surface and on its outer periphery, wherein the bump forming film is disposed on the base electrode forming surface of the electronic component in such a way that the bumps of the bump forming film according to any one of claims 1 to 10 are made into bumps of the base electrode by means of a conductive filler for the bumps. 24. The electronic component of claim 23, wherein 8 to 20 conductive fillers for bumps are disposed on the base electrode and its outer periphery. 25. A semiconductor device having bumps disposed on a substrate electrode for bumping on its surface and on its outer periphery, wherein the bump forming film is disposed on the substrate electrode forming surface of the semiconductor device in such a way that the bumps of the bump forming film according to any one of claims 1 to 10 are made into bumps of the substrate electrode by means of a conductive filler for the bumps. 26. The semiconductor device of claim 25, wherein 8 to 20 conductive fillers for bumps are disposed on the substrate electrode and its outer periphery.