JPH07220784A - Grain arranging plate and grain arranging method - Google Patents

Abstract

PURPOSE:To manufacture easily at a low cost a grain arranging plate for arranging conductive grains with small dispersion of quantity further with good accuracy on a supporter. CONSTITUTION:A grain arranging plate 2 having grain arranging holes 3 is formed by direct drawing ablation work using laser. Here, forming a grain arranging hole wall surface in a tapered shape is preferable. A holding plate 10 is connected to a reverse surface part of the grain arranging plate 2, and after a conductive grain 1 is vacuum sucked through the holding plate 10, a vacuum is released or a positive pressure is applied, to transcribe the conductive grain 1 in an arranging position on a supporter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a particle arranging plate and a particle arranging method used for arranging conductive particles on a circuit board electrode terminal for electrical conduction.

[0002]

2. Description of the Related Art A method of directly connecting electrodes of a semiconductor chip such as an IC, an LSI, and a chip capacitor to a substrate circuit on which a predetermined circuit is formed on the surface of a substrate made of resin, glass, ceramics or metal, or these substrates. As a so-called high-density electrode connection method such as connection between circuits, a method is known in which these electrodes (or circuits) facing each other are connected via a connecting member containing an adhesive as a main component.

Examples of these connecting members include conductive particles such as carbon particles, nickel, solder, or plastic particles having a conductive layer formed on the surface thereof in an insulating adhesive as disclosed in Japanese Utility Model Laid-Open No. 62-107444. When a conductive adhesive mixed with is used to obtain an electrical connection in the thickness direction by pressing, and when an insulating adhesive is used without using a conductive material and pressure is applied at the time of connection, electrical contact is made by direct contact with the electrode surface. A method is known in which a connection is obtained and the remaining adhesive is removed outside the circuit to connect.

In the case of a semiconductor chip as a typical example of high-density electrodes, protruding electrodes called bumps are often formed on the chip surface, and the bumps may also be provided on the substrate circuit. In any case, in the case where bumps are formed, the subsequent process becomes complicated, the yield decreases due to the occurrence of defects, and the bump materials Au, Ag, C are used.
There is a problem that the manufacturing cost becomes high due to consumption of precious metal such as u or solder.

In the connection method using an adhesive using conductive particles, when the number of particles on an electrode is increased in order to improve the reliability of electrical connection, particles are present in a high density between adjacent electrodes. As a result, there is a problem in maintaining the insulation such that the insulation becomes poor and a leak or a short circuit occurs. On the contrary, if the number of particles is reduced, the number of particles on the electrode becomes insufficient and the connection reliability deteriorates. This contradictory tendency is further promoted by the phenomenon that the conductive particles flow out from the electrodes together with the adhesive due to heating and pressing at the time of connection, and it is difficult to cope with high-density connection with a pitch of 90 μm or less, for example. there were.

In addition, the connection method using only an insulating adhesive has a good insulation property between adjacent electrodes, but has a drawback that it is difficult to obtain reliable connection reliability due to variations in bump height. That is, the number of bumps per chip is as large as 10 to 500, and the height of bumps is 1
It is about 50 μm. It is extremely difficult to form and control the large number of these electrodes with variations within 0.5 μm, for example.

Recently, for example, JP-A-63-276237 and JP-A-63-28 have been used for the purpose of breaking down the bottleneck of the above connection method.
There is also an attempt to form a conductive adhesive only on the bumps and connect it to a substrate circuit, as seen in Japanese Patent Publication No. 9824. In these methods, a conductive adhesive application step is required to form a conductive adhesive in a necessary portion, but by introducing an volatile organic solvent into a semiconductor manufacturing step in which cleanliness is particularly required, There are problems such as deterioration of cleanliness and deterioration of working environment. Furthermore, the method of applying a conductive adhesive to a necessary portion or forming it by a transfer method is close to the limit in terms of silk screen, transfer jig, etc., and it has been difficult to cope with higher density.

To solve this problem, Japanese Patent Laid-Open No. 4-30138
In JP-A-3, after applying an adhesive to a peelable substrate,
A step of bringing a mask having particle arrangement holes (having the same action as the particle arrangement plate of the present invention) into close contact with the adhesive surface, disposing conductive particles on the mask, and bringing the adhesive material into contact with the conductive particles; After that, a method is proposed in which the mask material is removed to obtain an electrical connection between the electrodes by using conductive particles arranged with an adhesive on a peelable substrate.

According to the above-mentioned proposal, it is possible to connect high density electrodes having excellent connection reliability and insulating property in a small area, and whether or not bumps are formed on a semiconductor chip and / or a circuit. It can be applied and has an advantage that it is not necessary to bring an organic solvent or a conductive adhesive into the semiconductor process.

However, in the above-mentioned particle arrangement method,
Since the conductive particles are arranged in the adhesive layer on the substrate through the particle arrangement holes, the particle arrangement hole diameter needs to have a margin of 20 μm or more with respect to the particles in consideration of variations in particle diameter. There is a drawback that the alignment accuracy of the particles becomes poor.

Further, the number of conductive particles arrayed through the particle array holes varies. Furthermore, when general electroformed Ni is used as the mask material, it requires a resist pattern formation and electrodeposition process, which requires time for manufacturing the mask, resulting in an increase in cost.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a conductive particle arranging plate which is capable of arranging conductive particles on a support through particle arranging holes with a small number variation and with high accuracy, at a simple and low cost. It is intended to make. Another object of the present invention is to provide a method for accurately transferring and arranging conductive particles at the arrangement position on a support using the above-mentioned particle arrangement plate.

[0013]

Means and Actions for Solving the Problems In order to solve the above problems, the present invention has a particle arrangement hole for arranging conductive particles with a small number variation and with high accuracy. In the particle array plate, the particle array plate is characterized in that the particle array holes are formed by direct drawing ablation using a laser.

Further, the present invention proposes the particle array plate, wherein the particle array plate is formed so that the wall surface of the particle array hole is tapered by controlling the laser light output.

The present invention also proposes a particle array plate, characterized in that the material of the particle array plate is resin, glass, ceramics or metal.

Further, according to the present invention, a holding plate is joined to the back surface of the particle array plate, the conductive particles are vacuum-adsorbed through the holding plate to position the particles at the array position, and then the vacuum is released or We propose a method for arranging particles which is characterized in that conductive particles are transferred to the arrangement position of a support by applying a positive pressure.

Furthermore, the present invention proposes a particle arranging method characterized by using a holding plate made of a porous body in the above-mentioned particle arranging method.

The present invention will be described in detail below. The present invention is
Adhere a particle array plate having particle array holes on a support,
An electrode using the conductive particles arranged on the support by peeling and removing the particle array plate material through the step of placing the conductive particles in the particle arrangement holes and bringing the support and the conductive particles into contact with each other. In order to obtain electrical connection between them, a particle array plate having particle array holes formed at arbitrary positions for arraying conductive particles can be easily obtained.

That is, in the particle array plate of the present invention, since the array holes are formed by the direct writing method by laser ablation, it is complicated to perform pattern formation by photolithography and electrodeposition as in the conventional array plate. A particle array plate in which conductive particles are arrayed on a support can be easily prepared without going through a particle array plate manufacturing step by steps. The support in the present invention is preferably used as a releasable substrate coated with an adhesive, but is not limited to this.

It is desired that the conductive particles easily enter the array holes of the particle array plate. Since the particle array plate of the present invention can control the hole wall taper angle, it is possible to obtain an optimum hole shape that matches the array particle diameter.

FIG. 1 is a diagram showing the behavior of particles when the taper angle of the hole wall is changed. For example, when the taper angle is small as shown in FIG.
It is necessary to reduce the dispersion of the particles, or the particles are not easily removed from the particle array holes 3 of the particle array plate 2. Also,
If the taper angle is too large, the particles may overlap in the holes as shown in FIG. 1C, and the number of particles after transfer may vary, or the particle position accuracy may deteriorate, resulting in high-density mounting. Not suitable. Therefore, an optimum taper angle, for example, as shown in FIG.
The state as shown in (a) is required.

In the particle array plate of the present invention, resin, glass, ceramics or metal can be selected as a material for the array plate, so that it is also possible to select, for example, a fluorine-based resin having good particle removal. By selecting glass, the arrangement of the conductive particles can be easily adjusted from the point that the arrangement can be performed while confirming the arrangement state of the particles.

In the particle array method of the present invention, since the holding plate is bonded to the back surface, the conductive particles can be vacuum-sucked, and the positional displacement at this time is small. Further, when the particles are arranged by vacuum adsorption, the suction force is concentrated on the non-adsorption portion, so that the non-arrangement portion can be further reduced. Besides, after vacuum suction positioning, release the vacuum on the back side of the array plate,
Alternatively, by setting a positive pressure, the conductive fine particles can be reliably transferred. Further, at this time, if a holding plate made of a porous material is bonded to the back surface, the array plate can be maintained with a higher degree of flatness, so that more accurate particle array can be performed.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

As a method for forming the conductive particle array plate in the present invention by direct drawing ablation using a laser, for example, an apparatus as shown in FIG. 2 can be considered. That is, after controlling the energy of the laser beam 5 output from the oscillator 4, the laser beam 5 is shaped by the lens unit 6, cut into a desired shape by the variable aperture 7, and irradiated on the substrate 9 by the projection lens 8 for direct drawing. To do.

At this time, the XYZ-θ of the table and the laser irradiation are comprehensively controlled so that the holes can be punched at any position of the array plate. In this example, the aperture shape is a quadrangle, but it may be a circle, and it is also possible to project a plurality of apertures at the same time.

In the present invention, in order to make the wall surface of the particle array holes tapered by controlling the laser light output,
A relationship as shown in FIG. 3 is seen between the laser fluence (laser energy density) and the taper angle, and the wall shape can be arbitrarily controlled by determining the laser fluence. The material of the particle array plate is resin, glass,
It can be made of ceramics or metal, but it goes without saying that it will vary depending on the material of the work piece with the tapered corner, the wavelength of the laser, and the processing atmosphere.

Further, in the present invention, a holding plate is joined to the back surface of the array plate, the conductive particles are vacuum-adsorbed through the holding plate, and the conductive particles are positioned at the array position, and then the vacuum is released or positive pressure is applied. By applying, it is possible to transfer the conductive particles to the arrangement position of the particles. In this specific example, FIG. 4 shows a structure in which the back surface of the holding plate 10 arranged on the back surface of the particle array plate 2 is connected to a pump and a compressor, and the internal pressure can be controlled to detach the conductive particles 1.

At this time, the holding plate joined to the back surface of the array plate is made of a porous sintered body such as SUS, so that the particle array plate can be formed at any position. It becomes possible to hold and make a flat surface.

[0030]

According to the present invention, since the particle array holes of the particle array plate are formed by the direct drawing ablation process using a laser, the number of conductive particles is varied on the support through the particle array holes. It is possible to easily and inexpensively produce an array plate of conductive particles that can be arrayed with a small amount and with high accuracy. Further, according to the present invention, a holding plate is bonded to the back surface of the particle array plate, the conductive particles are vacuum-adsorbed through the holding plate, and the particles are positioned at the array position, and then the vacuum is released or positively applied. By applying pressure, the conductive particles can be transferred to the arrayed positions on the support more accurately.

[Brief description of drawings]

FIG. 1 is a diagram showing the behavior of particles when the taper angle of particle array hole walls is changed.

FIG. 2 is a diagram showing an apparatus for forming a particle array plate by direct drawing ablation using a laser.

FIG. 3 is a diagram showing a relationship between a laser fluence and a taper angle.

FIG. 4 is a diagram showing an example of a particle arrangement method of the present invention.

[Explanation of symbols]

 1 conductive particles, 2 particle array plate, 3 particle array hole, 4 oscillator, 5 laser light, 6 lens part, 7 variable aperture, 8 projection lens, 9 substrate, 10 holding plate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshihiro Yoshida 1-3-6 Nakamagome, Ota-ku, Tokyo Stock company Ricoh Co., Ltd. (72) Tsutomu Sakazu 1-3-6 Nakamagome, Ota-ku, Tokyo Shares Inside Ricoh Company (72) Inventor Toshiaki Iwabuchi 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd. (72) Inventor Satoshi Kuwazaki 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Company ( 72) Inventor Katsuyuki Okubo 1-3-6 Nakamagome, Ota-ku, Tokyo Within Ricoh Co., Ltd.

Claims (5)

[Claims] 1. A particle array plate having a particle array hole for accurately arraying conductive particles on a support, and the particle array hole is a direct ablation using a laser. A particle array plate, which is formed by processing. 2. The particle array plate according to claim 1, wherein the wall surface of the particle array hole is formed in a tapered shape by controlling the laser light output. 3. The particle array plate according to claim 1, wherein the material of the particle array plate is resin, glass, ceramics or metal. 4. A holding plate is joined to the back surface of the particle array plate according to claim 1, 2 or 3, and the conductive particles are vacuum-adsorbed through the holding plate and positioned at the array position. A method for arranging particles, wherein conductive particles are transferred to an arrangement position on a support by releasing a vacuum or applying a positive pressure. 5. The method for arranging particles according to claim 4, wherein a holding plate made of a porous material is used.