JPH0338084A - Connection of circuit board - Google Patents

Abstract

PURPOSE:To make possible the stable connection between electrodes at a fine pitch without inflicting damage on circuit boards by a method wherein the bump electrode is connected by pressing to the electrode to correspond to the bump electrode through conductive particles. CONSTITUTION:A bonding agent 22 is selectively applied on a bump electrode 13 of a first circuit board 11, conductive particles 21 are adhered on the bonding agent 12, then, a second circuit board 12 with an electrode formed at a position, where corresponds to the electrode 13 of the board 11, of the board 12 and the board 11 are made to oppose to each other, are pressed to each other and in this state, the bonding agent 22 is hardened and both boards 11 and 12 are fixed. Accordingly, even if irregularity in height is generated in the electrode 13, the particles 21 are deformed at the time of connection and absorb the irregularity. Thereby, the stable connection between the electrodes 13 and 14 at a fine pitch becomes possible without inflicting damage on the boards 11 and 12.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is useful for connecting a circuit board on which protruding electrodes are formed, such as a semiconductor substrate, a ceramic substrate, a flexible substrate, a glass substrate, or an alint substrate, to another @N substrate. The present invention relates to a circuit board connection method suitably implemented for connection.

BACKGROUND OF THE INVENTION Conventionally, as a method for connecting metal protruding electrodes of the various circuit boards mentioned above to electrodes of other circuit boards, protrusions 1! A method is used in which a material that can be alloyed with the protrusion a4 pole material is used as the t-pole material of the circuit board to which the poles are connected, and the electrodes are metal-bonded. However, according to this method, the electrode material of the circuit board to which the protruding electrode should be connected is limited, so in recent years, metal protruding electrodes have been pressure-bonded onto the circuit board electrodes either directly or through an anisotropic conductive material. A method has been proposed to obtain physical connections.

Problems to be Solved by the Invention However, in the above connection method, it is necessary to apply excessive pressure to the electrode part to deform the protrusion ti in order to eliminate connection instability caused by variations in the height of the metal protrusion electrode. However, there is a problem that it may damage the circuit board, and since the sandwicher uses an anisotropically conductive or electrically conductive material, the resolution is poor and it is difficult to stabilize the connection resistance when connecting micropitch electrodes. There is a problem.

An object of the present invention is to solve the above-mentioned problems and provide an arbitrary circuit board having metal protruding electrodes. To connect a square circuit board to another circuit board having a pole material in a stable state even in minute pitch connections without damaging the square circuit board.

Means for Solving the Problems The present invention connects a first circuit board having protruding electrodes and a second circuit board having electrodes formed at positions corresponding to the protruding electrodes on the first circuit board. In this process, the process includes a step of selectively applying an adhesive to the top of the protrusion of the first circuit board, a step of attaching conductive particles to the adhesive, and pressing the square circuit board facing each other to remove the protrusion. A method for connecting circuit boards, comprising the steps of: electrically connecting an electrode to the corresponding electrode through conductive particles; and curing the adhesive in this state.

Function: In the circuit board connection method according to the present invention, an adhesive is first selectively applied onto the protruding electrodes of a first circuit board having protruding electrodes, and then conductive particles are adhered onto the adhesive. Next, a second circuit board having electrodes formed at positions corresponding to the protruding electrodes of the first circuit board and the first circuit board are placed facing each other and pressed together. In this state, the conductive particles on the first circuit board may be deformed, and some of the adhesive may be transferred to 'Xff!' on the second circuit board. Adhere to the top. Then, the square circuit board is fixed by curing the adhesive in this state.

Therefore, according to the present invention, even if there is a height variation in the protruding electrodes, the conductive particles deform and absorb it during connection, so that a stable connection can be obtained without damaging the circuit board. I can do it. Further, since the conductive particles are arranged at a high density only in the electrode portions, it is possible to connect the electrodes at a minute pitch.

Embodiment FIG. 1 is a sectional view showing the structure of a circuit board 11, 12 on which electrode connections are made according to the present invention.

A semiconductor circuit board 11 such as an integrated circuit has a diffusion layer formed on a substrate such as silicon or gallium arsenide, and a large number of transistors, diodes, etc. are formed thereby. On one surface of the semiconductor circuit board 11, there are three protrusions connected to the circuit board 12: four poles and one pole.On one surface of the circuit board 12, there are protrusions connected to the circuit board 12 at positions corresponding to the electrodes 13. The electrode 14 is formed according to the size.

An electrode 15 is formed on the top layer of the semiconductor circuit board 11 h,
A surface protective layer 2o made of, for example, SjN, SiO, or polyimide is applied to a portion of the electrode 15 and a portion where no electrode is provided. The electrode 15 includes, for example, Al-8i metal.

Consists of p4i, Ti, W, etc.

Further, on the electrode 15 of the semiconductor circuit board 11, an intermediate amount j
A protrusion 18 made of, for example, Au and Au plated f,2 Cu is formed through the Jc layer 19-.

In this embodiment, the intermediate & stratified layer 19 is an electric [! It consists of a barrier metal layer 16 on the 15 side and an adhesion layer 17 on the protrusion 18 side.

The adhesion layer 17 is for improving adhesion with the protrusion 18, and is made of, for example, CLl.

Metals such as Ni, Au, Ag, Pt, and alloys thereof can be used. The barrier metal layer 16 is for preventing the projections 18 provided on the adhesive layer 17 from diffusing and reacting with the electrodes 15, and is made of, for example, Ti.
, W, Cr, etc. and their base metals can be used. These electrodes 15, intermediate metal layer 19 and protrusions 18
The protruding electrode 13 includes the above. The height h of the protrusion type [i13 is, for example, 5 to 30 μm.

Semiconductor circuit board W, 1 on which the above-mentioned protruding electrode 13 is formed
1 are electrically connected to the corresponding electrodes 14 of the circuit board 12 via conductive particles 21 having an outer diameter of, for example, 5 to 20 μm, and are connected by an adhesive 22!
L et al. are fixed.

The conductive particles 21 include Au, Ag, Pt, Cu, Ni,
C, I rI, S rt , P b 13 and P
It is possible to use two or more types of metals, such as metals, or two or more of these metals.

Further, as shown in FIG. 2, a wave 71 layer 21a made of a conductive material is formed on the surface of the elastic particle 21b made of a polymeric material.
It is also possible to use conductive particles 21 formed with
As the elastic particles 21b, synthetic resins such as polyimide resins, epoxy resins, and acrylic resins, and rubbers such as silicone rubber and urethane rubber can be used. Also,
The conductive material of the coating layer 21a includes Au, Ag, and PL.
.

Cu, Ni, C, Irr, Sr+, Pb and Pd
Metals such as or alloys thereof can be used as one layer or two or more layers. Covering layer 21 with two or more layers
In field 1 where A is formed, a metal layer such as Ni, which can be absorbed into the adhesion of the elastic particles 21b/\, is first formed, and then A is formed.
It is preferable to coat the metal layer such as u, and as a coating method, a method such as a sputtering method, an electron beam 21 method, or an electroless plating method can be used.

As the adhesive 22, 8ib resins such as acrylic resin, polyester resin, urethane resin, epoxy resin, or silicone resin can be used.

Referring to FIGS. 3 and 4, the method for connecting circuit boards of the present invention will be described below.

FIG. 3 is a cross-sectional view for explaining the process of forming the protruding electrode 13 on the semiconductor circuit board 11.

As shown in FIG. 3(1), an electrode 15 is previously formed on the semiconductor circuit board 11, and the periphery of the electrode 15 is covered with a surface protective layer 20. First, an intermediate metal layer 19 for forming protruding electrodes is formed on the surface of the semiconductor circuit board 11 including the electrodes 15 by a vapor deposition method such as a sputtering method or an electron beam method, or a plating method. In this case, the intermediate metal layer 19 has a two-layer structure, and is made of 4 layers of Au (800 layers) / T i ・W alloy (2
400 people) structure was used.

Next, as shown in Figure 3 (2) to Figure 3 <5>,
A protrusion 18 is formed in a predetermined region where the protrusion $ pole 13 is to be formed using a photo process, a plating process, or an etching process.

First, as shown in No. 311J(2), a photoresist film 23 is coated on the semiconductor circuit board 11 on which the intermediate metal layer 19 is formed by a method such as a spin code, roll coating, or printing.

Next, as shown in the third IJ (3), a region of the photoresist film 23 corresponding to the electrode 15 is exposed and developed to form the opening 24 with desired size and formation. ning.

Next, as shown in the third [ff1(4)], electric plating is performed using, for example, an All plating solution through the opening 24 formed by the buttering to form the protrusion 18. do. Thereafter, by removing the photoresist Wi23, a protrusion 18 having the shape shown in FIG. 3(5) is formed on the semiconductor circuit board 11.

30(6) and 3(7)), using the protrusion 18 formed by the above method as a mask, the intermediate metal layer 19 other than the portion where the protrusion electrode 13 is to be formed is removed by etching. That is, in this embodiment, since Au (upper 7 FI 17)/Ti-W (lower layer 16) is used as the intermediate metal layer 19 and Au is used for the protrusion 18, the upper layer 17 of Au [/1 liquid (etchant)] is used. The intermediate metal layer 19 is etched and removed using a potassium iodide-based etchant as the etching agent and a hydrogen peroxide-based etchant as the etching solution for Ti--W, which is the lower layer 16.
9, the upper layer 17 has the same AU as the protrusion 18, so the surface of the protrusion 18 is etched when the upper layer 17 is etched. The amount of nitching is small and does not cause any problems in the process.
is formed on the semiconductor circuit board 11.

Next, referring to FIG. 4, the protrusion 5Tu is
A method of connecting the semiconductor circuit board 11 on which the fi 13 is formed to the circuit board W, 12 on which the corresponding electrode 14 is formed will be explained.

First, as shown in FIG. 4(1), an adhesive layer 22a is formed on the adhesive supply substrate 25 by a method such as spin coating, roll coating, or printing.

As adhesives, thermosetting materials made of the materials mentioned above,
A photocurable adhesive or the like can be used.

Next, as shown in FIG. 4(2), by pressing the protruding electrode 13 of the semiconductor circuit board 11 onto the adhesive N 22 a of the adhesive supply board 25, the adhesive is applied onto the protruding electrode 13. 22 is attached.

Next, as shown in FIG. 4(3), the protruding electrodes 13 on the semiconductor circuit board 11 to which the adhesive 22 has been attached in this manner are arranged almost uniformly on the conductive particle supply substrate 26. By pressing the conductive particles 21 onto the conductive particles 21 as shown in FIG.
3, the conductive particles 21 are attached to the conductive particles 21 as shown in FIG. It is necessary to select it appropriately depending on the value, and it is usually preferable to set 1 = d/2, for example, d = 5 to 20 μm.

Next, as shown in FIG. 4(6), the protrusions on the semiconductor circuit board 11 on which the conductive particles 21 have been attached in this manner are connected to the poles 13 on the circuit board 1 on which the corresponding electrodes 14 are formed.
After aligning on 2, apply pressure. Due to this pressurization, the conductive particles 21 are deformed so as to absorb variations in the height of the protruding electrodes 13, and all the protruding electrodes 13 correspond to the corresponding electrodes 1.
It is electrically connected to 4. Furthermore, since the conductive particles 21 are deformed in this state, a portion of the adhesive 22 flows and covers the electrodes 14 on the circuit board 12.

Next, by curing the adhesive 22 in this state, the connection and fixation of both circuit boards 11 and 12 is completed.

In the above embodiments, a case has been described in which a semiconductor circuit board on which protruding electrodes are formed is connected to another circuit board, but it is not necessary to limit it to semiconductor circuit boards, and the present invention can also be implemented on other circuit boards. I can do it.

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the protrusions tI[I are connected to the corresponding electrodes through conductive particles under pressure, so that it is possible to connect the protrusion electrodes to any electrode material. . In addition, even if there is variation in the height of the protrusion 1, the conductive particles are deformed during connection and can be absorbed, so it is possible to maintain a stable structure without damaging the circuit board. You can get a connection. Furthermore, since the conductive particles are arranged at a high density only in the electrode portions, stable Ti connections with fine pitches are possible.

[Brief explanation of drawings]

FIG. 1 shows circuit boards [11, 12
FIG. 2 is a cross-sectional view of the conductive particles 21 used in the present invention, and FIG. 3 is a cross-sectional view of the protruding electrode 13.
FIG. 4 is a sectional view illustrating a method of forming both circuit boards 11 and 12 according to the present invention. 11... Semiconductor circuit board, 12... Circuit board, 13
... protruding electrode, 14...'rh pole, 21... conductive particles, 22... adhesive diagram

Claims (1)

[Claims] A first circuit board having a protruding electrode, and a second circuit board having an electrode formed at a position corresponding to the protruding electrode on the first circuit board.
When connecting the first circuit board to the first circuit board, a step of selectively applying an adhesive onto the protruding electrodes of the first circuit board, a step of attaching conductive particles to the adhesive, and a step of placing the two circuit boards facing each other. and applying pressure to electrically connect the protruding electrode to the electrode at the corresponding position via the conductive particles, and curing the adhesive in this state. How to connect the board.