JPH02192195A - Connection structure of plural circuit boards - Google Patents

Abstract

PURPOSE:To enable the formation of connecting electrodes at a fine pitch by a method wherein a first circuit board is fixed to a second circuit board previously provided with a connecting electrode in a pressure-welded state. CONSTITUTION:A semiconductor device 1 and a sealing cover 6 are made to face a circuit board 5 making a connecting electrode 3 of the semiconductor device 1 confront a connecting electrode 7 of the circuit board 5, and the electrodes 3 and 7 are pressure-welded to each other in the direction of an arrow P as they are mutually aligned. A joining photosetting adhesive agent 11 is injected between the sealing cover 6 and the circuit board 5 in the pressure welding state, and the semiconductor device 1 and the sealing cover 6 are mounted on the circuit board 5 by setting the adhesive agent 11 through irradiation with ultraviolet rays. In this state, the semiconductor device 1 is electrically connected with the circuit board 5 as the connecting electrode 3 is pressure- welded to the connecting electrode 5 with the sealing cover 6. By this setup, the electrodes 3 and 7 positioned at a fine pitch can be connected with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides electrical connection between an L-product circuit board on which semiconductor elements are formed, and a circuit board such as a printed circuit board, a flexible board, a glass substrate, or a ceramic board. The present invention relates to a connection structure for a plurality of circuit boards that is suitably implemented for connection to a plurality of circuit boards.

Conventional technology In recent years, IC (Int+4rated C1rcuit
) As the degree of integration of semiconductor integrated circuit boards increases, the number of input/output terminals also tends to increase. In response to this, the conventional wire bonding method, in which the input/output terminals of a semiconducting water board are electrically connected to the electrodes of a wiring board using conductive wires such as gold or aluminum, is being used. A flip-chip method is used in which protruding electrodes are provided on the upper input/output terminals and connected all at once to electrodes on the wiring board.

With this flip-chip method, the electrodes are connected by pressure welding rather than soldering, as shown in the following (a) to (c).
) and other advantages.

(a) Since there is no need to heat the semiconductor substrate and the circuit board during connection, the semiconductor substrate and the circuit board are not damaged by heat.

(b) Since the connection is not made by soldering, the electrode monthly rate of the circuit board is not limited to the parent solder metal material. (c) Although the semiconductor board is only fixed to the circuit board by pressure welding, after the connection The semiconductor substrate can be easily replaced when a defect occurs in a circuit element of the semiconductor substrate.

Due to these advantages, various methods have been proposed in recent years, such as a method of press-contacting via a conductive connector and a method of press-contacting a protruding electrode formed of a metal material.

For example, JP-A-61-242041. Japanese Unexamined Patent Publication No. 61-25
9548. JP-A-63-150930 discloses a method for forming elastic, conductive protruding electrodes on a circuit board. By using such a protruding electrode having elasticity and conductivity, there is no need to provide an intermediate object such as the conductive connector at the connection portion. Further, since the protruding electrodes themselves have elasticity, irregularities in height of the protruding electrodes and "undulations" of the circuit board to be connected can be absorbed by this elasticity during pressure contact.

Problems to be Solved by the Invention All of the above-mentioned methods employ printing methods such as screen printing or light irradiation through a mask plate in which through-holes are formed corresponding to the positions of protruding electrodes to be formed on the circuit board. In this method, protruding electrodes are formed by selectively curing conductive ink that has been applied in advance on a circuit board. With a printing method or a photolithography method using a mask plate, it is difficult to form minute protruding electrodes corresponding to electrodes having a minute pitch width. Therefore, there was a problem that electrodes having a minute pitch width could not be connected to each other.

SUMMARY OF THE INVENTION An object of the present invention is to provide a connection structure for a plurality of circuit boards, which solves the above-mentioned problems and allows interconnection of electrodes having fine pitch widths.

Means for Solving the Problems The present invention provides a base material having circuit wiring formed on at least one surface thereof, and electrically connected to the circuit wiring at a connection region,
a first circuit board including a connection electrode whose remaining region is spaced from the base material with an intervening body having elasticity and electrical insulation properties; and the remaining region of the connection electrode on the first circuit board. and a second circuit board on which connection electrodes are formed at corresponding positions, and the remaining areas of the connection electrodes of the first circuit board are opposed to the connection electrodes of the second circuit board, and these are pressed together. This is a connection structure for a plurality of circuit boards, characterized in that the circuit boards are fixed in a fixed state.

Function In the present invention, circuit wiring is formed on at least one surface of the base material of the first circuit board, and the connection region of the connection electrode is electrically connected to the circuit wiring. Further, the remaining regions of the connection electrodes are provided at a distance from the base material with an intervening body having elasticity and electrical insulation properties interposed therebetween. Further, a connection electrode is formed on the second circuit board at a position corresponding to the remaining area of the connection electrode on the first circuit board. The remaining region of the connection electrode of the first circuit board having such a configuration is opposed to the connection electrode of the second circuit board, and the first and second circuit boards are fixed in pressure contact with each other. Ru.

Therefore, according to the present invention, it is possible to form connection electrodes at a fine pitch on the first circuit board with the intervening body interposed therebetween. In addition, irregularities in the heights of the connection electrodes of the first and second circuit boards and "waviness" of the circuit board are absorbed by the elastic deformation of the intervening body during pressure welding, making it possible to obtain a stable and uniform connection structure. can. In addition, in the event that a defect occurs in an electronic component mounted on at least one of the first and second circuit boards, one circuit board can be easily removed from the other circuit board and a new, non-defective circuit board can be easily removed. You can replace it with a new circuit board.

Embodiment FIG. 1 is a perspective view of a semiconductor device 1, which is a first circuit board according to the present invention. In the semiconductor device 1, on a substrate 2, which is a base material on which circuit wiring, which will be described later, is formed, a connecting electrode 3, which is electrically connected in a connection area of the circuit wiring, is provided on the substrate 2 with elastic and They are formed in a spaced-apart manner with an intervening body 4 having electrical insulation properties interposed therebetween, according to a method described later.

FIG. 2 is a perspective view showing a state in which the semiconductor device 1 is mounted on a circuit board 5, which is a second circuit board.

In FIG. 2, the front side of the drawing of the semiconductor device 1 and the sealing cover unit 6 is cut away to clearly show the mounting state of the semiconductor device 1. A connection electrode 7 is formed on the circuit board 5 at a position corresponding to the connection electrode 3 of the semiconductor device 1 . Therefore, each connection electrode 3 of the semiconductor device 1 is opposed to each connection electrode 7 of the circuit board 5, and the semiconductor device 1 and the circuit board 5 are fixed in a press-contact state.

A recess 6a is formed in the upper surface of the sealing cover 6, and the semiconductor device 1 is pressed against the circuit board 5 by the recess 6a of the sealing cover 6.

FIG. 3 is a sectional view taken along the section line l11-I in FIG. 1, and FIG. 4 is a partially enlarged sectional view of FIG. The substrate 2 of the semiconductor device 1 has a diffusion layer formed on a wafer of silicon or gallium arsenide, and constitutes a semiconductor integrated circuit in which a large number of transistors, diodes, etc. are formed.

In the semiconductor device 1, an electrode 8 is formed on the top layer of a substrate 2,
A portion of the electrode 8 other than the connection region where the connection electrode 3 is formed is coated with a surface protection layer 9 made of, for example, SiN, SiO2, PSG (glass), or polyimide. Further, an elastic and electrically insulating intervening body 4 having a predetermined thickness 11 is formed at the peripheral edge of the surface protection N9 that the substrate 2 is coated with. On the surface of the electrode 8 exposed from the intervening body 4 and the surface protection layer 9, a connecting electrode 3 is formed in the shape shown in, for example, FIGS. 1 and 4 by a method described later.

As the intervening body 4, an electrically insulating resin that becomes an elastic body after hardening, such as silicone resin or polyimide resin, is used. Further, as the connection electrode 3, for example, A1
, Ti, C (1-N16 gold, Au, etc.).

The intervening body 4 is formed by uniformly applying a photocurable resin onto the substrate 2 of the semiconductor device 1 in advance by, for example, a method such as spin cord or roll coating. The applied photocurable resin is irradiated with ultraviolet rays through a mask plate in which through holes are selectively formed so that only the peripheral portion of the substrate 2 is cured, as shown in FIG. As a result, only the peripheral portion on the substrate 2 is cured, and the area surrounded by the peripheral portion is left uncured. By etching this uncured area using a developer, for example, 11=10
It can be formed as an intervening body 4 having a predetermined shape and having a thickness of ~20 μm.

When the thickness 11 of the intervening body 4 is thinner than 10 to 20 μm, for example, about 11-1 to 3 μrn, the intervening body 4 can eliminate the unevenness of the electrode 37 when the semiconductor device 1 is mounted on the circuit board 5. Therefore, the adhesion between the semiconductor device 1 and the circuit board 5 deteriorates. In addition, when 11 is thick, for example, when 11 = 50 μm, the boundary portion becomes unclear when the intervening body 4 made of photocurable resin is selectively cured by ultraviolet rays, etc., and the accuracy of pattern formation decreases. Put it away.

On the substrate 2 of the semiconductor device 1, the connection electrode 3 is formed after the above-mentioned intervening body 4 is formed. The connection electrode 3 is, for example, A1. Ti, Cu-Ni alloy, Au
It is formed of a metal film having a multilayer structure consisting of:

Among these, the A1 layer, the Ti layer, the Cu-Ni alloy layer, etc. are uniformly formed to a predetermined thickness on the substrate 2 of the semiconductor device 1 using a thin film forming technique such as vapor deposition or sputtering. do. Next, a photoresist layer is formed on these metal layers by, for example, a method such as a spin code, and after prebaking at a predetermined temperature, a mask plate is formed which is selectively patterned only in the portion where the connection electrode 3 is to be formed. A photoresist layer is exposed using a photoresist, and a photoresist pattern is formed using a predetermined developer. Next, each metal layer is sequentially etched using the seven photoresist patterns as a mask, and the photoresist layer is peeled off to form a predetermined metal layer pattern. Further, on top of these metal layers, an A L1 layer is formed, for example, by electroless plating.

The above A1 layer is preferably formed to have a layer thickness of about 1000 rr m, and is similar to the AI electrode 8 formed on the substrate 2.
Al is used from the viewpoint of adhesion to. The Ti layer formed on this A1 layer preferably has a layer thickness of about 300 rr m, and is laminated for corrosion resistance and oxidation prevention of the A1 layer. Further, the Cu-Ni alloy layer preferably has a thickness of about 3 Q Q nm, and from the viewpoint of adhesion with the AU layer described later, Cu
is used. However, since Cu alone is easily oxidized,
Used as a Cu-Ni alloy with Ni. Like this A1
On top of the Ti layer, the Cu-Ni alloy layer and the Ti layer, an Au layer is further formed to prevent oxidation of the whole.
It is formed with a thickness of about 00 ri rn.

FIG. 5 is a sectional view showing the process of mounting the semiconductor device 1 on which the connection electrode 3 is formed as described above on the circuit board 5 using the sealing cover body 6, and FIG. 1
FIG. 3 is a cross-sectional view showing a state in which is mounted on a circuit board 5. FIG.

Therefore, FIG. 6 is a sectional view taken along the section line Vl--Vl in FIG. 2.

The semiconductor device 1 in which the connection electrode 3 is formed with the intervening body 4 interposed in advance has a convex surface whose opposite surface to the surface on which the connection electrode 3 is formed is the back surface of the four parts 6a of the sealing cover integral 6. Part 6
b using, for example, an adhesive 10 that hardens at room temperature. In this state, the height 114 of the connection electrode 3 of the semiconductor device 1 joined to the sealing cover unit 6 is set to be greater than the height h2 of the sealing cover unit 6.

The semiconductor device 1 and the sealing cover integrated 6 are
The connection electrode 7 of the circuit board 5 to which the connection electrode 3 of the circuit board 5 is connected.
and are pressed together in the direction of arrow P in a mutually aligned state. In this pressurized state, a photocurable adhesive 11 for bonding is injected between the sealing cover unit 6 and the circuit board 5, and is cured by irradiation with ultraviolet rays, etc., and then the semiconductor device 1
Then, the sealing cover unit 6 is mounted on the circuit board 5. In this state, the connection electrode 3 of the semiconductor device 1 is pressed against the connection electrode 7 of the circuit board 5 by the sealing cover unit 6, and is electrically connected. Therefore, the height h3 of the sealing cover unit 6 relative to the circuit board 5 after sealing is set within the range of the following formula, which is larger than the height h2 shown in FIG. 5 and smaller than the height h4. .

h 2 h 3 < h 4 ・・
- (1) In the state of the first equation, the intervening body 4 of the semiconductor device 1 is in an elastically deformed state. As a result, it is possible to absorb unevenness such as unevenness in the heights of the connection electrodes 3 and 7 of the semiconductor device 1 and the circuit board 5, or "undulations" of the circuit board 5, and The electrical connection of each connection electrode 3.7 can be made stable and uniform.

Furthermore, if a defect occurs in the semiconductor device 1, since the semiconductor device 1 is simply pressed onto the circuit board 5, the defective semiconductor device 1 can be easily removed from the circuit board 5. The semiconductor device 1 can be replaced with a new semiconductor device 1 without any defects.

FIG. 7 is a perspective view of a semiconductor device 12 which is another embodiment of the present invention, FIG. 8 is a sectional view taken along the section line ■-■ in FIG. FIG. 3 is an enlarged sectional view for showing a part of the figure in detail. Note that the same reference numerals are used for parts corresponding to the embodiments shown in FIGS. 1 to 6.

An electrode 8 is formed in advance on the substrate 2 of the semiconductor device 12, and a surface protection layer 9 is formed on a portion other than the connection area of the electrode 8. Further, on the surface protection layer 9, a seventh
An intervening body 4 is formed at the peripheral edge of the substrate 2 in the shape shown in FIG. 8 and FIG. The intervening body 4 has a layer thickness 11=10
~20μrl'l. A connecting electrode 13 is formed with the intervening body 4 interposed in the shape shown in FIG. 9 and having an abbreviated cross section. This connection electrode 13 is similar to the connection electrode 3 shown in FIG.
It is formed of a metal thin film having a multilayer structure made of , Ti, Cu-Ni alloy, Au, or the like.

By forming the connection electrode 13 in the shape shown in FIG. 7 on the substrate 2 of the semiconductor device 12, the area of the connection electrode 13 can be reduced compared to the semiconductor device 1 shown in FIG. It is possible to downsize. Therefore, the mounting area of the semiconductor device 12 is also reduced.

FIG. 10 is a sectional view showing a structure in which the semiconductor device 12 shown in FIG. 7 is mounted on the circuit board 5 using the sealing cover unit 14. An elastic member 15, such as silicone rubber, is bonded in advance to the recess of the sealing cover unit 14 using an adhesive 16 that hardens at room temperature. The surface of the semiconductor device 12 opposite to the surface on which the connection electrode 13 is formed is bonded to the elastic member 15 via an adhesive 17.

The semiconductor device 12 bonded to the sealing cover unit 14 in this manner is pressed into contact with the connection electrodes 13 of the semiconductor device 12 in such a manner that they are aligned with the connection electrodes 7 of the circuit board 5 . In this pressure-welded state, the sealing cover 1
A photocurable adhesive 11 is injected between the photocurable adhesive 4 and the circuit board 5, and the semiconductor device 12 is mounted on the circuit board 5 by curing the photocurable adhesive 11 by irradiating ultraviolet rays or the like.

In this embodiment, uneven heights of the connection electrodes 13 of the semiconductor device 12 and undulations of the circuit board 5 are eliminated by the semiconductor device 12 being pressed against the circuit board 5, and thereby the intervening body 4 and This can be absorbed by elastic deformation of the elastic member 15. Therefore, the connection electrode 13 of the semiconductor device 12 and the connection electrode 7 of the circuit board 5 are electrically connected in a more stable and uniform state.

In the two embodiments related to the semiconductor device 1.12 described above, the shapes of the connecting electrodes 3.13 formed and the integral sealing covers 6, 14 used during pressure bonding are different from each other. However, the present invention includes any combination of such members, and is not limited to such combinations or shapes of each member.

As described in detail, according to the present invention, connection electrodes can be formed on the first circuit board with an intervening body at a fine pitch width. By fixing the first circuit board in pressure contact with the second circuit board on which connection electrodes are formed in advance, the height of the connection electrodes formed on the first and second circuit boards increases. It is possible to absorb irregularities in the circuit board and "waviness" of the circuit board by elastic deformation of the intervening body, and the connection electrodes of the first and second circuit boards are connected to each other in a stable and uniform state. Furthermore, since the first and second circuit boards are only fixed in pressure contact with each other, for example, if a defect occurs in an electronic component mounted on the first circuit board, it is easy to damage the first circuit board. The board can be removed from the second circuit board and replaced with a new, non-defective first circuit board.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a semiconductor device 1 which is an embodiment of the present invention, FIG. 2 is a perspective view showing a state in which the semiconductor device 1 is mounted on a circuit board 5, and FIG. 3 is a cross-section line of FIG. 1. 4 is a partially enlarged sectional view of FIG. 3, FIG. 5 is a sectional view explaining the mounting process of the circuit board 5/\ of the semiconductor device 1, and FIG. 6 is a semiconductor 7th cross-sectional view showing the mounting state of the device 1
The figure is a perspective view of a semiconductor device 12 which is another embodiment of the present invention, FIG. 8 is a cross-sectional view taken along the cutting plane line ■--■ in FIG. 7, and FIG. 9 is a partially enlarged cross-section of FIG. 10 are cross-sectional views showing how the semiconductor device 12 is mounted on the circuit board 5. As shown in FIG. 1.12...Semiconductor device, 2...Substrate, 3.7.13...
...Connection electrode, 4...Intermediate body, 5...Circuit board, 6
14... Sealing cover integrated, 8... Electrode, 9... Surface protective layer, 10.11, 16.17... Adhesive, 15
...Elastic member, P...Press contact direction agent Patent attorney Keiichi Nishikyo

Claims (1)

[Scope of Claims] A base material having circuit wiring formed on at least one surface thereof, and an intervening body electrically connected to the circuit wiring in a connection region and having elasticity and electrical insulation properties from the base material in the remaining region. a first circuit board including connection electrodes spaced apart from each other; and a second circuit board on which the connection electrodes are formed at positions corresponding to the remaining areas of the connection electrodes on the first circuit board. The remaining areas of the connection electrodes of the first circuit board face the connection electrodes of the second circuit board, and are fixed in a press-contact state. Connection structure.