JP2002324819A - Ic mounting board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an IC mounting with a simple, easy manner and high reliability even when there are no bumps on the IC side. SOLUTION: In forming the bump 2 to be an IC mounting terminal portion by covering a surface of a protruding portion 11 arranged on a surface of a base material with a conductive metal layer to be a circuit pattern, a surface of the bump 2 is formed so that minute unevenness 20 with a surface roughness Ra 0.1-3 μm continues. A connection resistance is significantly reduced by existence of the minute unevenness 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an IC mounting substrate for directly mounting an IC.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No.
JP-A-220533 discloses a method in which a protrusion is provided on the surface of a substrate of a substrate, a conductive metal layer is formed on the surface of the protrusion to form a bump, and an IC is placed on the bump via a conductive paste and heated. A device for bonding a terminal portion of an IC to a bump is shown.

Japanese Patent Application Laid-Open No. 9-511873 discloses that a three-dimensional molded circuit board (MID substrate) made of a polymer resin is formed with a protrusion at the same time, and a conductive pattern forming a circuit pattern on the surface of the protrusion is formed. IC by forming metal layer
It is disclosed that bumps are used as terminal portions for mounting.

[0004] I with a bump formed as described above
The substrate for C mounting can be mounted without solder bumps on the IC side.
C can be mounted, but if the heights of the bumps are not uniform, a connection failure will be caused. On the other hand, the protrusions on the substrate cause variations in the upper surface height of each bump of about several μm due to the dimensional accuracy of the mold and the transferability from the mold to the molded product. Approximately 10μ due to warpage after molding the substrate
A variation of about m occurs.

At this time, the warpage of the substrate can be corrected by using the pressing force at the time of mounting the IC, and the difference in height can be absorbed if the bump itself has elasticity. It is possible to reduce the occurrence of connection failure. In particular, in the case of a three-dimensional molded circuit board made of the above-described polymer resin, the projections can be formed at the same time as the board is molded, and the projections made of the polymer resin have elasticity. good.

[0006]

However, in practice, ICs
If no bumps are formed on the terminal portions on the side, there are many problems in terms of IC bonding strength and the like at present, and mounting of ICs without bumps has elastic protrusions. It is not possible to cope with it only by providing a bump based on the part.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to mount an IC easily and with high reliability even if there is no bump on the IC side. Another object of the present invention is to provide an IC mounting substrate on which an IC can be mounted with higher reliability if the IC has bumps.

[0008]

According to the present invention, there is provided an IC mounting substrate, wherein a surface of a projection provided on a surface of a base material is covered with a conductive metal layer serving as a circuit pattern to form a terminal portion for IC mounting. The first feature of the bump formed is that the bump surface is a surface on which fine irregularities having a surface roughness Ra of 0.1 μm to 3 μm are continuous.

The fine irregularities on the bump surface may be formed by a conductive metal layer by plating, or may be formed on the surface of the protrusion of the base material.

The present invention has a second feature in that the protrusion has a rectangular shape and an open surface which is not covered with a conductive metal layer is formed on a side surface of the protrusion.

According to the present invention, the projection is formed as a ridge, and a plurality of conductive metal layers serving as a plurality of circuit patterns are formed at intervals on the surface of the ridge. It has the following characteristics. In this case, the protrusion may be formed in an annular shape. Further, a plurality of small protrusions may be formed at intervals on the surface of the protrusion, and a conductive metal layer may be provided on the surface of each small protrusion.

Further, the present invention is mounted on an IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a projection provided on a surface of a base material with a conductive metal layer serving as a circuit pattern. A fourth feature is that a protrusion, whose front end surface is in contact with the IC, is provided integrally with the substrate. It is preferable that the protrusions are provided inside and around the region surrounded by the bumps.

The present invention also relates to an IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a protrusion provided on a surface of a base material with a conductive metal layer serving as a circuit pattern. Has a fifth feature in that a recess is provided at the position corresponding to the protrusion in the above, and a recess is provided on the surface of the substrate, and a bump formed of the protrusion and the conductive metal layer is provided in the recess. Has the sixth feature. The protrusion provided in the recess is preferably formed of a material softer than the base material, and the protrusion as a separate component formed of a material softer than the base material may be press-fitted and fixed in the recess. Good. Further, it is preferable that the projection is made of a low melting point filler, and the conductive metal layer covering the surface of the projection is provided with an opening that allows the low melting point filler to leak out.

The base material may have a groove on the surface surrounding the bump formation area, or may have an underfill mounted on the bump formation area of the base material by transfer molding. It is preferable that the cross section of the fill is an arc shape with a raised center.

The protrusion may be formed of a conductive material.

In manufacturing an IC mounting substrate in which a bump as an IC mounting terminal portion is formed by covering the surface of a protrusion provided on the surface of a base material with a conductive metal layer serving as a circuit pattern, the protrusion is formed. It is possible to suitably use a method in which the projection is cured in the mold by irradiating ultraviolet rays, using a mold made of an ultraviolet transmitting material for the mold.

In addition, a projection may be formed by coating a secondary molding material layer on an injection-molded base material, and then compressing and molding it with a projection molding die.

A projection may be formed on the injection-molded substrate by dispensing or ink-jetting.
In this case, dispensing or inkjet may be repeated a plurality of times.

Further, a secondary molding material layer is coated on the injection molded base material, and then a resin material for forming a protrusion is further placed on the secondary molding material layer. The protrusion may be formed by compression molding with a mold.

After forming a projection and covering the surface of the projection with a conductive metal layer serving as a circuit pattern to form a bump as an IC mounting terminal, an underfill is mounted on the bump formation region by transfer molding. At this time, if the cross-sectional shape of the underfill is an arc with a raised center, more preferable results can be obtained.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an example of an embodiment. FIG. 1 shows a schematic configuration of an IC mounting substrate 1 according to the present invention. (Many) protrusions 11 are provided, and the surface of the protrusions 11 is covered with a conductive metal layer 12 constituting a circuit pattern, thereby forming bumps 2 which are IC mounting terminal portions. .

Although the substrate 10 is shown as a flat plate in the figure, a three-dimensional molded circuit board (MID board)
What is formed as can be suitably used. The protrusion 11 has a width of about 100 μm and a height of 100 μm.
The conductive metal layer 12, which is formed by plating and forms a circuit pattern, is formed by plating nickel plating 12b having a thickness of about 5 to 10 μm on copper plating 12a having a thickness of about 5 to 10 μm. Is formed by applying gold plating 12c having a thickness of about 0.3 to 0.5 μm. The surface of the bump 2 has a surface roughness Ra of 0.1 μm or more.
It is a surface on which fine irregularities 20 of 3 μm are continuous.

The fine irregularities 20 can be formed by applying a matte nickel plating 12b under the gold plating 2c as the surface layer when forming the conductive metal layer 12 on the projection 11 formed as a smooth surface. However, as shown in FIG. 2, the surface of the conductive metal layer 12 is plated by plating.
The surface of the protruding portion 11 on which is formed the continuous irregularities 20 ′, and when the conductive metal layer 12 is formed on this surface, the minute irregularities 20 appear on the surface of the conductive metal layer 12. Good. The provision of the fine irregularities 20 ′ on the surface of the protrusion 11 is, for example, as shown in FIG. The molding material of the base material 10)
It can be obtained by removing the filler 19 present on the surface of the protrusion 11 by etching after molding the base material 10 having the protrusion 11 using a material containing the filler 19. In this case, the conductive metal layer 1 by plating
2, it is possible to obtain the fine unevenness 20 having a larger surface roughness than the case where the fine unevenness 20 is formed.

By the way, in the case where the minute unevenness 20 was provided on the surface of the bump 2 and the case where the minute unevenness 20 was not provided, mounting of the IC using the silver paste (each sampling number of 50) was performed. As shown in FIG. By providing the fine irregularities 20, the connection resistance value could be greatly reduced. That is,
When the minute irregularities 20 having the surface roughness Ra of 0.13 μm were provided, the connection resistance could be reduced to 50 mΩ or less.
Those without the fine irregularities 20 (surface roughness Ra0.0
6 .mu.m), the connection resistance value becomes approximately 50 m.OMEGA. Or more, and an IC with a low connection resistance value can be mounted.

The reason why the above-mentioned difference occurs in the connection resistance value is considered to be that the contact area between the silver paste and the silver particles 9 is increased as shown in FIG. FIG. 4B shows the contact area with the silver particles 9 when the surface roughness of the bump 2 is Ra 0.01 μm.

When the minute irregularities 20 are provided, as shown in FIG. 5, the minute irregularities 20 on the surface of the pad 2 break through the oxide film layer 31 on the surface of the terminal portion 30 formed as an aluminum pad of the IC 3. Gold plating 12 of bump 2
The layer c is directly in contact with the aluminum portion of the terminal portion 30 at multiple points without the interposition of the oxide film layer 31.

FIG. 6 shows another example of the bump 2. In the bump 2 here, the protrusion 11 serving as a base has a rectangular shape in a plan view, and the conductive metal layer 12 forming the circuit pattern has the upper surface and two side surfaces of the protrusion 11. , But the other two side surfaces of the protrusion 11 are formed as not covered. In this case, the terminal 3 of the IC 3 is longer in the longitudinal direction of the rectangular bump 2 than in the bump 2 having the round protrusion 11 as a base.
It is possible to increase the allowable amount Z of the displacement of 0, and also to reduce the distance (pitch) P between the bumps 2 in the short direction of the bumps 2 as shown in FIG.

Furthermore, since the two side surfaces of the protrusion 11 are open surfaces not covered with the conductive metal layer 12, the protrusion 1
1 is made to have elasticity and the protrusion 11
When the protrusions are bent, the deformability of the protrusions 11 is higher than in the case where the entire surface of the protrusions 11 is covered with the conductive metal layer 12, and therefore, the height variation of the protrusions 11 is absorbed. Can be enhanced.

FIG. 8 shows a projection 11 having a projection 11 '.
And a plurality of conductive metal layers 12 forming a plurality of circuit patterns formed at intervals on the surface of the ridge 11 '. As the circuit pitch becomes narrower, it becomes difficult to form the ultrafine projection 11 with a mold. However, by forming the projection 11 ′ and forming a plurality of circuit patterns on the surface, the narrow pitch can be obtained. It becomes easy.

When the IC 3 has terminals on its four sides, the ridge 11 'is preferably formed in an annular shape as shown in FIG. 8B. To prevent "swell" due to the occurrence of "swell" due to thermal stress, as compared to the case where four independent ridges 11 'are provided, the annular ridge 11' serves as a rib to restrain. Can be.

As shown in FIG. 9, if a plurality of small protrusions 13 are formed at intervals on the surface of the protrusion 11 'and the conductive metal layer 12 is provided on the surface of each small protrusion 13, the conductive Metal layer 12
Since the creepage distance between them becomes longer and it becomes easier to secure insulation, the circuit pitch can be further reduced.

FIGS. 10 and 11 show another example. This is because the protrusions 1 are formed outside the region where the bumps 2 are formed on the substrate 10.
4 is provided so that the tip end surface of the protrusion 14 is brought into contact with the IC 3 mounted by bonding the terminal 30 to the bump 2. The protrusion 14 functions as a stopper.
To prevent excessive exposure. The projection 14 is shown in FIG.
As shown in FIG. 0 (b), it may be an annular shape surrounding the formation region of the bump 2.

Further, as shown in FIG. 12, by providing the projections 14 also in the region where the bumps 2 are formed,
The gap can be kept constant over the entire surface even if there is warpage or undulation, and the pressing force at the time of mounting
Over concentration can be prevented.

FIG. 13 shows an example in which a concave portion 15 is provided at a position corresponding to the protrusion 11 on the back side of the base material 10 having the protrusion 11 on the front surface. The area of the recess 15 is preferably larger than the cross-sectional area of the projection 11. The presence of the recess 15 reduces the rigidity of the protrusion 11 (bump 2) in the base material 10, so that the height variation of the mounting surface can be suppressed with a low load when the IC 3 is mounted. It will be.

As shown in FIG. 14, a recess 16 may be provided on the surface of the base material 10 and the bump 2 composed of the protrusion 11 and the conductive metal layer 12 may be provided in the recess 16. Base material 10
Since the height of the bump 2 from the back surface of the IC 3 can be suppressed, the thickness can be reduced while ensuring the stress relaxation effect when the IC 3 is mounted.

In this case, the protrusion 11 is not formed integrally with the base material 10 but is formed of a material softer than the base material 10 in the recess 16 of the base material 10 as shown in FIG. If this is the case, the stress relaxation effect can be further enhanced.
In this case, the protrusion 11 can be obtained by forming the base 10 by two-color molding, and the protrusion 1 is provided in the recess 16.
It can be formed by dispensing a resin as a material of the first material or dropping it by an ink jet method. Further, the protrusion 11 formed as a separate component may be press-fitted and fixed in the recess 16 as shown in FIG. 16 (a) or 16 (b). In this case, the positioning of the protrusion 11 can be performed.

FIG. 17 shows another example. The projecting portion 11 is formed of a low melting point filler, and the conductive metal layer 2 covering the surface of the projecting portion 11 has a groove 25 on its upper surface.
And an opening 26 on the side surface. The opening 26 here is for letting the low-melting filler forming the protrusion 11 leak out to the outside by heating and pressurizing at the time of mounting the IC 3, and the low-melting filler leaked into the recess 16. Fills the recesses 16 and enters the grooves 25 and contributes to the temporary fixing of the IC 3. As compared with the paste pre-coating method, since the bump 2 is not covered with the sealing resin (underfill), it is not necessary to remove the sealing resin on the bump 2 for mounting, and the conduction reliability can be improved. it can.

As shown in FIG. 18, when the underfill 8 is mounted on the mounting surface of the IC 3 and then the mounting of the IC 3 is performed, the groove 18 surrounding the formation region of the bump 2 is formed on the surface of the base material 10. If provided, the underfill 8 can be prevented from flowing out by the groove 18.

When the underfill 8 is used for mounting the IC 3, the underfill 8 is applied by applying a paste.
As shown in FIG. 19, a difference in height occurs between the bumps 2 and between the bumps 2 on the upper surface of the underfill 8, and after the IC 3 is mounted, a void 80 is formed between the bumps 2.
May occur. To prevent this, the solidified underfill 8 may be formed by transfer molding on the base material 1 provided with the bumps 2. As shown in FIG. 20, since the height of the surface of the underfill 8 can be made uniform, the void 80 does not occur. The underfill 8 molded in a solidified state becomes a paste state when left in an environment at room temperature to about 50 ° C., and the IC 3 is mounted at this time.

In the transfer molding of the underfill 8, as shown in FIG. 21, if the underfill 8 is formed to have an arc-shaped cross section with a raised center, the generation of voids can be more reliably suppressed. it can.

By the way, the protrusion 11 on the base material 10
When the substrate 10 is formed as a three-dimensional molded circuit board (MID substrate), as shown in FIG.
The protrusions 11 may be formed simultaneously during the injection molding. However, as shown in FIG. 23, after the base material 10 having no protrusions 11 is once injection-molded, The protrusion 11 can be formed by putting the base material 10 in the mold 7 and performing re-melt compression molding.

When the protrusion 11 is formed of a material having a higher elasticity than the base material 10 (or softer than the base material 10), the protrusion 11 may be made of a thermoplastic resin, a thermosetting resin, or an ultraviolet-curable resin. Resin, a two-pack curable resin, or the like. In particular, when the base material 10 is made of a polyphthalamide resin mixed with an inorganic filler, as a material for forming the protrusions 11, a non-filler-reinforced poly A phthalamide resin can be suitably used. Then, when forming the protrusion 11, as shown in FIG. 24, the protrusion 11 is formed by performing insert injection molding on the base material 10 that has been injection-molded, and solidified by cooling (thermoplastic resin).
Alternatively, in addition to a general two-color molding method of heat-curing (thermosetting resin), as shown in FIG. 25, a mold 7 for forming the protrusions 11 may be made of a UV-transmitting material such as glass. Alternatively, the curing may be performed by ultraviolet irradiation from outside the mold 7.

As shown in FIGS. 26 and 27, a secondary molding material layer is coated on the base material 10 by injection, spin coating, doctor blade, or the like. Next, the protrusions 11 may be formed by compression molding and curing with a mold 7 for molding the protrusions 7. FIG. 27 shows a case in which curing is performed by irradiation of ultraviolet light from outside the mold 7 made of the UV transmitting material.

In addition, as shown in FIGS. 28 and 29, a resin material for the protrusion 11 is placed on the injection-molded base material 10 by dispense or ink jet, and the spherical shape is held by the surface tension of the resin material. , Then solidification (U
As described above, the protrusions 11 may be formed by performing V curing. In the case where the protrusion 11 is formed by dispensing, the above-described protrusion 11 'is also used in FIG.
32, and the protrusion 11 (protrusion 11 ') having the small protrusion 13 can be formed by repeating dispensing and curing a plurality of times as shown in FIG. it can. Alternatively, a rubber-like or gel-like material having a relatively lower elastic modulus than the base material 10 after curing may be used.

As shown in FIG. 30, the base material 10 formed by injection molding was used.
Then, using a dispense, spin coating, doctor blade or the like, a secondary molding material layer is coated on the base material 10 to coat the secondary molding material layer, and further dispensing or ink jetting is performed on the secondary molding material layer. Then, a resin material for the protrusion 11 may be placed thereon, and then the protrusion 11 may be formed by compression-molding with a mold 7 for forming the protrusion. FIG. 30 (b) shows a case in which an ultraviolet transmitting material, for example, glass is used as the mold 7 so that the projection 11 can be cured by ultraviolet irradiation at this time.

In the case where the projection 11 is formed without using the mold 7, the size and height of the projection 11 cannot be defined by the mold 7. It is preferable to control the size (diameter and height) of the protrusion 11 by using measurement and the like. In the case where control is performed by image processing, the image processing is facilitated by setting the color of the forming material of the protrusion 11 to a color different from the color of the base material 10.

Further, irrespective of whether or not the mold 7 is used, the formed protrusion 11 is pressed against a member having a plane similar to that of the IC 3 by heat or ultra-high pressure prior to formation of the conductive metal layer 12. By giving an energy such as acoustic vibration that can melt and deform the material of the protrusion 11, the protrusion 1
If the flatness of the front end surface of the first member is increased, more preferable results can be obtained.

In addition, the protrusion 11 may be formed of a conductive material, for example, a conductive resin, a solder-mixed plastic, a material for powder metal injection molding, or the like. In this case, the conductive metal layer 12 formed by plating is formed. The amount of adhesion at the protrusion 11 can be increased.

[0049]

As described above, in the IC mounting substrate according to the present invention, the surface of the protrusion provided on the surface of the base material is covered with a conductive metal layer serving as a circuit pattern to form bumps as IC mounting terminal portions. In the formed one, since the bump surface is a surface on which fine irregularities with a surface roughness Ra of 0.1 μm to 3 μm are continuous, the connection resistance value at the time of mounting the IC can be greatly reduced. ICs can be mounted with high reliability without bumps.
If there is a bump on the side, the IC can be mounted with higher reliability.

The bumps and bumps on the bump surface may be formed by a conductive metal layer formed by plating. However, if the bumps and bumps are formed on the protruding surface of the substrate, the bumps and bumps having a large surface roughness can be reduced. It can be obtained easily.

Further, according to the present invention, since the protrusion is formed in a rectangular shape and an open surface which is not covered with a conductive metal layer is formed on a side surface of the protrusion, the protrusion is provided with elasticity to make the IC
When the protrusion is bent by the pressing force at the time of mounting, the deformability of the protrusion is higher than when the entire surface of the protrusion is covered with the conductive metal layer, and therefore, Absorption of the height variation of the protrusion can be obtained with a low pressing force.

Further, according to the present invention, the protrusion is formed as a ridge, and a plurality of conductive metal layers serving as a plurality of circuit patterns are formed at intervals on the surface of the ridge. The pitch of the circuit pattern can be reduced by the conductive metal layer that becomes the circuit pattern without being restricted by the molding of the fine structure in the mold.

In this case, if the ridge is formed in an annular shape,
The generation of “undulation” due to thermal stress can be prevented by the ridge that functions as a restraining rib.

If a plurality of small protrusions are formed at intervals on the surface of the ridge and a conductive metal layer is provided on the surface of each small protrusion, the creeping distance between the conductive metal layers becomes longer, and the insulating property increases. Since the securing is easy, the circuit pitch can be further reduced.

Further, the present invention is mounted on an IC mounting substrate in which a bump serving as an IC mounting terminal is formed by covering a surface of a protrusion provided on a surface of a base material with a conductive metal layer serving as a circuit pattern. A fourth feature is that a protrusion, whose front end surface is in contact with the IC, is provided integrally with the substrate. It is preferable that the protrusions are provided inside and around the region surrounded by the bumps.

The present invention also relates to an IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a projection provided on a surface of a base material with a conductive metal layer serving as a circuit pattern. Since the recess is provided at the position corresponding to the protrusion in the above, the rigidity of the protrusion (bump) portion of the base material can be reduced by the recess, and the height of the mounting surface can be reduced with a low load when mounting the IC. Variation can be suppressed.

Further, according to the present invention, since a concave portion is provided on the surface of the substrate and a bump composed of a protrusion and a conductive metal layer is provided in the concave portion, the height of the bump from the back surface of the base material is increased. Therefore, the thickness can be reduced while the effect of relaxing stress during mounting of the IC is ensured.

In this case, the stress relief effect can be further enhanced by forming the projection provided in the recess with a material softer than the base material. Further, a protrusion as a separate component formed of a material softer than the base material may be press-fitted and fixed in the recess. Protrusions effective for absorbing variations in height of the mounting surface can be easily obtained.

The protruding portion is made of a low melting point filler, and the conductive metal layer covering the protruding portion is provided with an opening for allowing the low melting point filler to leak to the outside. The low melting point filler fills the space inside the recess and contributes to the temporary fixing of the IC. In addition, the bump is not covered with the sealing resin (underfill) in the paste pre-coating method. It is not necessary to eliminate the sealing resin in the above, and the conduction reliability can be increased.

If the base material has a groove on the surface surrounding the area where the bump is to be formed, the underfill can be prevented from flowing out by the groove.

If an underfill placed by transfer molding is provided in the bump formation area of the base material, the height of the underfill surface can be made uniform.
It is possible to eliminate a possibility that a void is generated on the mounting surface side of the IC. If the cross section of the underfill has an arc shape with a raised center, the generation of voids can be suppressed more reliably.

The protrusion may be formed of a conductive material. When the conductive metal layer is formed by plating, the thickness of the conductive metal layer in the protrusion (bump) serving as the IC mounting terminal can be increased.

In manufacturing an IC mounting substrate in which a bump as an IC mounting terminal portion is formed by covering the surface of the protrusion provided on the surface of the base material with a conductive metal layer serving as a circuit pattern, it is necessary to form the protrusion. When the projection is cured in the mold by irradiating ultraviolet rays, using a mold made of an ultraviolet transmitting material for the mold, it is possible to easily manufacture a substrate having the projection.

A secondary molding material layer is coated on an injection-molded base material, and then the projection is formed by compression molding with a projection molding die. The substrate can be easily manufactured.

Further, by forming projections on the injection-molded base material by dispensing or ink-jetting, it becomes easier to manufacture a substrate having projections without the need for a mold for molding projections. It can be carried out. In this case, by repeating the dispensing or the ink jet a plurality of times, it is possible to easily manufacture the substrate having the projection having the small projection.

Further, a secondary molding material layer is coated on the injection-molded base material, and then a resin material for forming a protrusion is further placed on the secondary molding material layer. The protrusion may be formed by compression molding with a mold.

[Brief description of the drawings]

FIG. 1 shows an example of an embodiment of the present invention, in which (a)
Is an explanatory view showing a state at the time of mounting the IC, and (b) is an enlarged cross-sectional view of the bump having the fine unevenness in the above.

FIG. 2 shows another example of a bump having fine irregularities.
(a) is an enlarged cross-sectional view, and (b) is an explanatory view of a method for forming minute unevenness on a protrusion of the bump.

FIG. 3 is an explanatory diagram showing a correlation between surface roughness and connection resistance value according to the first embodiment.

FIGS. 4A and 4B are cross-sectional views illustrating a contact area between a bump and silver particles in a silver paste.

FIG. 5 is a cross-sectional view showing a relationship between minute irregularities and an oxide film layer of a terminal portion of the IC when the IC is mounted.

6A and 6B show another example, in which FIG. 6A is a partial perspective view, and FIG. 6B is a sectional view.

FIG. 7 is a diagram illustrating a distance (pitch) between bumps according to the embodiment.

FIGS. 8A and 8B are perspective views of different examples.

FIGS. 9A and 9B are a perspective view and a cross-sectional view of still another example.

FIGS. 10A and 10B are perspective views of different examples.

FIG. 11 is an explanatory diagram showing the operation of the above.

FIG. 12 is an explanatory diagram showing an operation in another example of the above.

FIG. 13 is an explanatory diagram showing an operation in another example.

FIG. 14 is an explanatory diagram showing an operation in still another example.

FIG. 15 is an explanatory diagram showing an operation in a different example.

FIGS. 16A and 16B are cross-sectional views of different examples.

17A and 17B are perspective views of another example, and FIG. 17C is an explanatory view showing an operation.

FIG. 18 is an explanatory diagram showing an operation of a different example.

FIG. 19 is an explanatory diagram showing the operation of a conventional example.

FIG. 20 is an explanatory diagram showing an operation of an example in the present invention.

FIG. 21 is a sectional view of another example of the above.

FIG. 22 is an explanatory diagram illustrating an example of the manufacturing method.

FIG. 23 is an explanatory diagram of another example of the above.

FIG. 24 is an explanatory diagram of still another example of the above.

FIG. 25 is an explanatory diagram of another example of the above.

FIG. 26 is an explanatory diagram of still another example of the above.

FIG. 27 is an explanatory diagram of a different example from the above.

FIG. 28 is an explanatory diagram of another example of the above.

FIG. 29 is an explanatory diagram of still another example of the above.

FIGS. 30 (a) and (b) are explanatory diagrams each showing an example of a manufacturing method.

FIG. 31 is an explanatory diagram of another example.

FIG. 32 is an explanatory diagram of still another example.

[Explanation of symbols]

 2 Bump 10 Base material 11 Protrusion 12 Conductive metal layer 20 Fine irregularities

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Masao Kubo, Inventor, Matsushita Electric Works Co., Ltd. 1048, Kazuma, Kadoma, Osaka Prefecture (72) Inventor Kimiaki Nakada 1048, Kazuma, Kazuma, Kadoma, Osaka, Japan Matsushita Electric Works, Ltd. 72) Inventor Hiroyuki Yoshida 1048 Kadoma, Kadoma, Osaka Pref., Matsushita Electric Works, Ltd. (72) Inventor Kazunori Kuzuhara 1048 Kadoma, Kazuma, Kadoma, Osaka Pref. Matsushita Electric Works, Ltd. (72) Inventor, Shinobu Kida Osaka 1048 Kadoma, Kamon, Fumonma-shi Matsushita Electric Works Co., Ltd. F-term (reference) 5F044 KK01 KK17 KK18 KK19 LL13

Claims (25)

[Claims] 1. An IC mounting substrate in which a bump serving as an IC mounting terminal is formed by covering a surface of a protrusion provided on a surface of a base material with a conductive metal layer serving as a circuit pattern, the surface of the bump is roughened. An IC mounting substrate characterized by having a surface with fine irregularities of Ra 0.1 μm to 3 μm continuous. 2. The IC mounting substrate according to claim 1, wherein the fine irregularities on the bump surface are formed by a conductive metal layer formed by plating. 3. The IC mounting substrate according to claim 1, wherein the fine irregularities on the bump surface are formed on the surface of the protrusion of the base material. 4. An IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a protrusion provided on a surface of a base material with a conductive metal layer serving as a circuit pattern, wherein the protrusion has a rectangular shape. And an open surface not covered with a conductive metal layer is formed on a side surface of the protrusion. 5. An IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a projection provided on a surface of a base material with a conductive metal layer serving as a circuit pattern, wherein the projection is formed by a projection. And a plurality of conductive metal layers serving as a plurality of circuit patterns formed at intervals on the surface of the protrusion. 6. The IC mounting board according to claim 5, wherein the ridge is formed in an annular shape. 7. The small projection according to claim 5, wherein a plurality of small projections are formed at intervals on the surface of the projection, and a conductive metal layer is provided on the surface of each small projection. IC
Mounting board. 8. An IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a protrusion provided on a surface of a base material with a conductive metal layer serving as a circuit pattern, An IC mounting substrate, characterized in that a protrusion that comes into contact with a surface is integrally formed on the substrate. 9. The IC mounting substrate according to claim 8, wherein the projections are provided inside and around a region surrounded by the bumps. 10. An IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a protrusion provided on a surface of a base material with a conductive metal layer serving as a circuit pattern, wherein the protrusion on the back surface of the substrate is provided. A substrate for mounting an IC, wherein a recess is provided at a position corresponding to a part. 11. An IC mounting substrate in which a bump as an IC mounting terminal portion is formed by covering a surface of a projection provided on a surface of a base material with a conductive metal layer serving as a circuit pattern, and forming a recess on the surface of the substrate. Wherein a bump comprising a projection and a conductive metal layer is provided in the recess.
Mounting board. 12. The IC mounting board according to claim 11, wherein the projection provided in the recess is formed of a material softer than the base material. 13. The IC mounting board according to claim 12, wherein the projection as a separate component formed of a material softer than the base material is press-fitted and fixed in the recess. 14. The protrusion is made of a low melting point filler, and the conductive metal layer covering the surface of the protrusion has an opening for allowing the low melting point filler to leak out. The substrate for mounting IC described in the above. 15. The IC mounting substrate according to claim 1, wherein the substrate has a groove on the surface surrounding the bump formation region. 16. The IC according to claim 1, wherein an underfill placed by transfer molding is provided in a bump forming region of the base material.
Mounting board. 17. The cross section of the underfill is formed in an arc shape with a raised center.
6. The IC mounting substrate according to 6. 18. The IC mounting substrate according to claim 1, wherein the protrusion is made of a conductive material. 19. In manufacturing an IC mounting substrate in which a bump as an IC mounting terminal is formed by covering a surface of a protrusion provided on a surface of a base material with a conductive metal layer serving as a circuit pattern, a method of forming the protrusion is used. A method for manufacturing an IC mounting substrate, comprising: using a mold made of an ultraviolet-transmitting material for a mold, and curing the protrusions in the mold by irradiating ultraviolet rays. 20. In manufacturing an IC mounting substrate in which bumps are formed as terminal portions for IC mounting by covering the surface of a projection provided on the surface of a base material with a conductive metal layer serving as a circuit pattern, a base formed by injection molding is used. What is claimed is: 1. A method for manufacturing an IC mounting substrate, comprising: coating a secondary molding material layer on a material; and then forming the projection by compression molding with a projection molding die. 21. In the manufacture of an IC mounting substrate in which bumps are formed as terminal portions for IC mounting by covering the surface of a protrusion provided on the surface of a base material with a conductive metal layer serving as a circuit pattern, a base formed by injection molding is used. A method for manufacturing an IC mounting substrate, comprising: forming a projection on a material by dispensing or inkjet. 22. The IC according to claim 21, wherein the dispensing or the ink jet is repeated a plurality of times.
A method for manufacturing a mounting substrate. 23. In manufacturing an IC mounting substrate in which bumps are formed as terminal portions for IC mounting by covering the surface of a projection provided on the surface of a base material with a conductive metal layer serving as a circuit pattern, a substrate formed by injection molding is used. A secondary molding material layer is coated on the material, then a resin material for forming a protrusion is further placed on the secondary molding material layer, and then the protrusion is formed by compression molding with a mold for forming a protrusion. A method for manufacturing an IC mounting substrate, comprising forming a portion. 24. After forming a protrusion and covering the surface of the protrusion with a conductive metal layer serving as a circuit pattern to form a bump as a terminal portion for mounting an IC, underfilling the bump formation region by transfer molding. The IC according to any one of claims 19 to 23, wherein the IC is mounted.
A method for manufacturing a mounting substrate. 25. The method of manufacturing an IC mounting substrate according to claim 24, wherein the cross-sectional shape of the underfill is an arc shape with a raised center.