JPH0864638A - Semiconductor device and production thereof - Google Patents

Abstract

PURPOSE: To sustain a good electrical connection between a semiconductor device and the wiring of a circuit board even if the ambient temperature increases over the glass transition point of a resin by forming a resin layer containing conductive particles on the protruding electrode of of a semiconductor element. CONSTITUTION: A UV-curing resin layer 4 is formed on a bump 3. The resin layer 4 is formed by dispersing conductive particles 5 of Ag substantially uniformly into a UV-curing resin. An IC bare chip device 1 is covered, on the periphery thereof, with a UV-curing resin paste 6 under a state where the resin layer 4 formed on the bumps touches the wiring 8 formed on a circuit board 7. Subsequently, the resin paste 6 is irradiated with UV rays and cured thus bonding the IC bare chip device 1 to the wiring 8. They are bonded through an effective connection area under a state where the conductive particles 5 in the resin layer 4 are crushed and deformed elastically. This structure can sustain a good electrical connection between the semiconductor device and the wiring formed on the circuit board.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device and its mounting structure, and more particularly to a bare chip component such as an IC or LSI mounted on a circuit board of an LCD module or a multi-chip module by using TAB, a flip chip method, or the like. Regarding its mounting structure.

[0002]

2. Description of the Related Art Conventionally, as a method of connecting a bare chip (bare chip not subjected to resin molding, etc.) such as an IC or LSI to a circuit board such as an LCD module or a multi-chip module, a protrusion provided on the bare chip. The TAB and flip chip methods using electrodes (bumps) are well known. For example, when using the flip chip method,
As shown in FIG. 5, the IC bare chip 11 uses a paste resin 15 such as a UV curable resin, and the Au bumps 12 formed on the lower surface of the IC bare chip 11 are formed on the wiring 14 made of Al or the like on the circuit board 13. , Mounted electrically connected. The volume of the resin 15 shrinks when it hardens, and internal stress is applied in the direction in which the Au bump 12 and the wiring 14 are attracted to each other, so that the Au bump 12 and the wiring 14 are in a pressure-bonded state.

Further, as shown in FIG. 6, the IC bare chip 11 has bumps 12 formed on wiring 14 coated with an anisotropic conductive resin paste 16 (a resin particle 161 having metal particles 17 dispersed therein). Are pressed so as to face a predetermined wiring 14, and the density of the metal particles 17 between the bumps 12 and the wiring 14 which face each other is increased so that the metal particles 17 come into contact with each other and are electrically connected to each other. However, the anisotropic conductive resin paste 16 is also cured and mounted.

The IC bare chip 11 is mounted on the wiring 14 of the circuit board 13 by the above two methods.

[0005]

However, when the above-mentioned conventional method is used, there are the following problems.
First, when the IC bare chip 11 as shown in FIG. 5 is connected by directly pressing the bump 12 to the wiring 14 by curing the resin 15, the surrounding environment is equal to or higher than the glass transition temperature (Tg) of the resin 15. In such a case, the cured resin 15 becomes fluid again, the internal stress of the resin 15 is released, and the pressure contact of the IC bare chip 11 to the circuit board 13 is not maintained. As a result, there is a problem that a poor connection occurs. Generally UV
Since the Tg of the curable resin is 100 ° C. or lower,
If the temperature exceeds 100 ° C., the problem of poor connection will occur.

Further, when the IC bare chip 11 as shown in FIG. 6 is connected to the circuit board 13 using the anisotropic conductive resin paste 16, the density of the metal particles 17 between the bumps 12 and the wirings 14 is reduced. In order to bring the metal particles 17 into contact with each other at a higher height, it is necessary to press the bump 12 against the wiring 14 with a relatively large force. However, when the pressing force is small, even if the force is small, the number of places where the metal particles 17 come into contact with each other decreases, and accordingly the electric resistance increases and the temperature in the vicinity thereof easily rises. Therefore, in the anisotropic conductive resin paste 16, the metal particles 17 having a smaller coefficient of thermal expansion than the resin 161 do not catch up with the expansion of the resin 161 due to the temperature rise, and the metal particles 17 and the metal particles 17 A gap is generated between the wire 17 and the wiring 14 or between the metal particle 17 and the bump 12 to cause poor contact. Therefore, the IC bare chip 11 is prone to electrical connection failure with respect to the circuit board 13, and there is a problem that reliability is significantly reduced.

The present invention has been devised under the above circumstances. In a structure in which a semiconductor device is electrically connected to wiring of a circuit board through a resin, the ambient environment is equal to or higher than Tg of the resin. An object of the present invention is to provide a semiconductor device and a mounting structure for the semiconductor device, which can favorably maintain the electrical connection state between the semiconductor device and the wiring of the circuit board even when the temperature rises.

[0008]

To solve this problem, the present invention provides a semiconductor device in which a resin layer containing conductive particles is provided on a protruding electrode of a semiconductor element. The present invention further provides the above semiconductor device, wherein the conductive particles are formed by coating the surface of a resin base material with a metal.

Further, the present invention provides any one of the above semiconductor devices in which conductive particles are spread in a layer in the resin layer so as to face the upper surface of the bump electrode. In addition, the present invention, in any one of the above semiconductor device, in a state in which a protruding electrode provided with a resin layer containing conductive particles is pressed against a predetermined wiring of a circuit board via the resin layer, The present invention provides a mounting structure for a semiconductor device, characterized in that the semiconductor device and the circuit board are fixed to each other with a resin interposed around the protruding electrode.

As the resin used for the resin layer, a UV curable resin, a thermosetting resin or the like can be used.
The thickness of the resin layer is preferably about 5 μm to 15 μm, more preferably about 8 μm to 12 μm.
As the conductive particles, a metal such as Au, Ni, or the like can be used, and the particle size thereof is preferably about 3 μm to 10 μm, more preferably about 4 μm to 6 μm.

The content of the conductive particles in the resin layer is preferably about 1% to 5%, more preferably about 2% to 3%. Further, when the conductive particles are formed by coating the surface of a resin base material with a metal, a vinyl resin, a polyester resin or the like can be used as the resin base material, and Ni, Au or the like can be used as the metal. .

[0012]

According to the semiconductor device of the present invention,
Since the resin layer containing conductive particles is provided on the protruding electrode of the semiconductor element, if the semiconductor device is electrically connected to the wiring of the circuit board through the resin layer, the resin layer is hardened. When only the internal stress that causes the resin layer to contract, the conductive particles are slightly elastically deformed but come into contact with the adjacent conductive particles, so that electrical connection becomes possible,
Moreover, since the number of contact points between the conductive particles does not increase more than necessary, it is possible to suppress an increase in electric resistance. That is, the conductive particles can be appropriately brought into contact with each other in the semiconductor device without applying an external force to the wiring of the circuit board.

Therefore, even if the semiconductor device is placed in an ambient environment above the Tg of the resin used for the resin layer, the thermal expansion of the resin layer causes the elastically deformed conductive particles to return to their original shape. Since the internal stress is released to the extent that it is possible to maintain contact between the conductive particles in the resin layer, it is possible to maintain a good energized state. Also,
In the present invention, when the resin base material whose surface is coated with a metal is used as the conductive particles, the conductive particles have internal parts even if they are exposed to a temperature not lower than the Tg of the resin as described above. Since the resin base material has a thermal expansion coefficient substantially the same as or similar to that of the surrounding resin, the resin base material expands almost in the same manner as the expansion of the resin layer, so that the electrically conductive state can be better maintained in the resin layer.

Further, in the present invention, when the conductive particles are laid one by one in the resin layer so as to face the upper surface of the protruding electrode, the conductive particles are contracted and expanded as described above. However, the resistance value does not become higher than necessary.
In addition, in the present invention, even when the semiconductor device is fixed to the predetermined wiring of the circuit board through the resin layer with the resin interposed around the protruding electrode to fix the semiconductor device and the circuit board, The conductive particles can keep the conductive particles in good contact with each other regardless of the contraction / expansion of the surrounding resin, and maintain a good electrical connection between the semiconductor device and the wiring of the circuit board. You can do it.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below by taking an IC bare chip component as a semiconductor device as an example with reference to FIGS. 1 to 4. However, the present invention is not limited to these. FIG. 1 is a sectional view of an essential part showing an IC bare chip component.

This IC bare chip component has a substantially rectangular parallelepiped-shaped IC bare chip 1, and electrode pads 2 formed in a thin plate shape made of aluminum on both sides of the surface of the IC bare chip 1 (both left and right sides in the figure). Bumps 3 (protruding electrodes) made of Au formed on both electrode pads 2 respectively
And a resin layer 4 made of a UV curable resin formed on each of the bumps 3.

The resin layer 4 is formed by coating the UV curable resin with A
The conductive particles 5 made of g are substantially uniformly dispersed, and the thickness thereof is about 10 μm. The particle size of the conductive particles 5 is about 5 μm. The bump 3 has a thickness of about 15 to 20 μm. The method of forming the resin layer of the IC bare chip component having such a structure includes, for example, the following method.

First, two plate-like members each having a groove having a depth of about 5 to 10 μm are prepared in advance, and the groove of one plate-like member is filled with a resin in a UV-curable paste state, and the other is formed. The conductive particles 5 are filled in the grooves of the plate member. Then, the resin is transferred onto the bump 3 of the IC bare chip component so that the bump 3 approaches the groove of one plate member.

After that, the conductive particles 5 are transferred onto the bumps 3 of the IC bare chip 1 so that the resin on the bumps 3 approaches the groove of the other plate-shaped member. In this case, since the resin has not been solidified yet, the conductive particles 5 enter the resin. Then, the bare IC chip 1 on which the resin and the conductive particles 5 are transferred onto the bumps 3 is irradiated with UV rays to cure the resin and form the conductive resin layer 4.

The resin layer 4 of the IC bare chip component thus obtained is formed on the bumps 3 with a substantially uniform and thin thickness. In addition, as shown in FIG. 2, this IC bare chip component is covered with a UV curable resin paste 6 in the state where the resin layer 4 on the bump 3 is in contact with the wiring 8 of the circuit board 7. After that, the resin paste 6 is irradiated with UV rays to cure the resin paste 6 to form the wiring 8.
When the conductive particles 5 in the resin layer 4 are fixed to the upper side, they can be connected in an effective connection area (effective contact area) while the conductive particles 5 in the resin layer 4 are crushed and elastically deformed. The elastic deformation amount of the conductive particles 5 is 1 to 2 μm in the above embodiment.
However, it is not limited to this.

In the present embodiment, the conductive particles 5 made of Ag are used, but the conductive particles 5 are not limited to this, and a metal such as Cu can be used. As the conductive particles, as shown in FIG. 3, the surface of the ball 9 made of various metal particles such as Ag or Cu or a resin base material such as vinyl resin is coated with a metal 10 such as Ni or Au. The thing etc. can be used. When the same resin as the resin in the resin layer 4 is used as the balls 9, the coefficient of thermal expansion of the conductive particles is equal to or close to the coefficient of thermal expansion of the resin. Can follow the expansion and contraction of conductive particles,
A better connection can be maintained. If the resin used as the balls 9 has a higher coefficient of thermal expansion than the resin around the conductive particles in the resin layer, the expansion and contraction of the conductive particles is further followed by the expansion and contraction of the resin due to the heat cycle. be able to.

Further, as shown in FIG. 4, if the conductive particles 5 are formed in the resin layer 4 such that they are spread one by one on the bumps 3 of the IC bare chip 1, the conductive particles 5 of the resin layer 4 can be formed. It is possible to significantly reduce variations in characteristics and formation state. In this case, it is preferable to use particles having a particle diameter of the conductive particles 5 that is approximately the same as or slightly smaller than the depth of the groove of the plate-shaped member. It is possible to easily spread the characteristic particles 5 one by one.

In the present embodiment, the electrode pad 2
Although the bumps 3 are directly formed on the bumps 3, the present invention is not limited to this, and a passivation layer made of SiN or the like is formed around the electrode pads 2 and further made of Ti, Pt or the like on the electrode pads 2. After forming the barrier metal layer,
The bumps 3 may be formed on the barrier metal layer. In addition, although the IC bare chip component is used in the present embodiment, the present invention is not limited to this, and is also applicable to a bare chip component such as an LSI or LCD.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an IC bare chip component of the present invention.

FIG. 2 is an explanatory diagram for explaining how the IC bare chip component of the present invention is mounted on a circuit board.

FIG. 3 is an explanatory diagram illustrating a modified example of conductive particles used in the IC bare chip component of the present invention.

FIG. 4 is an explanatory diagram illustrating an arrangement state of conductive particles of the IC bare chip component of the present invention.

FIG. 5 is a cross-sectional view for explaining connection by the flip chip method.

FIG. 6 is a cross-sectional view for explaining a connection using an anisotropic conductive resin.

[Explanation of symbols]

 1 IC Bare Chip 2 Electrode Pad 3 Bump 4 Resin Layer 5 Conductive Particle

Claims (4)

[Claims] 1. A semiconductor device in which a resin layer containing conductive particles is provided on a protruding electrode of a semiconductor element. 2. The semiconductor device according to claim 1, wherein the conductive particles are formed by coating the surface of a resin base material with a metal. 3. The semiconductor device according to claim 1, wherein the conductive particles in the resin layer are laid one by one so as to face the upper surface of the bump electrode. 4. The semiconductor device according to claim 1, wherein a bump electrode provided with a resin layer containing conductive particles is provided with a predetermined wiring on the circuit board via the resin layer. A mounting structure of a semiconductor device, wherein the semiconductor device and the circuit board are fixed to each other with a resin interposed around the protruding electrode in a state of being pressed against.