KR100720408B1 - Bonding Method and Device for Flip chip use of ACF - Google Patents

Abstract

The present invention provides a flip chip bonding method and a bonding apparatus using an anisotropic conductive film capable of performing flip chip bonding in a state of a film itself without individualizing the anisotropic conductive film when the flip chip is mounted on the supertor using an anisotropic conductive film .

The present invention is directed to a method of forming an anisotropic conductive film, comprising: depositing an anisotropic conductive film on a substrate;

Wherein the pick-up tool picking up the chip with the bump is placed on the chip pad of the supertor having the anisotropic conductive film on the surface thereof;

Separating the unit film necessary for chip mounting from the anisotropic conductive film;

And a step of thermocompression bonding the chip and the unit film to the chip pads of the superty while the separated unit film is attached to the bottom surface of the chip, the method comprising the steps of: providing a flip chip bonding method using the anisotropic conductive film; do.

The present invention also provides a semiconductor device, comprising: a substrate on which a semiconductor chip is mounted;

A pick-up tool that moves the semiconductor chip with the bumps attached thereto and mounts the semiconductor chip on the substrate;

An anisotropic conductive film positioned between the supertwand and the pick-up tool to which the chip is attached;

And film separating means for separating as much unit film as necessary for chip mounting from the anisotropic conductive film, wherein the pick-up tool thermally compresses the chips to the supersatellite while separating as much unit film as necessary for the supersatellite packaging A flip chip bonding apparatus using an anisotropic conductive film is provided.

Anisotropic conductive film (ACF), flip chip, pick-up tool

Description

TECHNICAL FIELD [0001] The present invention relates to a flip chip bonding method and an flip chip bonding method using an anisotropic conductive film,

1 is a cross-sectional view showing a conventional flip chip package.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flip chip bonding apparatus using an anisotropic conductive film (ACF).

FIGS. 3 to 5 are sectional views showing steps of a flip chip bonding method using the anisotropic conductive film of the present invention.

6A and 6B are plan views showing other embodiments of an anisotropic conductive film.

DESCRIPTION OF REFERENCE NUMERALS

2: semiconductor chip 4: bump

6: Substrate 6a: Chip pad

8: Anisotropic conductive film (ACF) 10: Substrate mount

20: Pickup tool 30: Punch

32: punch tip 82, 82a, 82b: unit film

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip chip bonding apparatus and a bonding method, and more particularly, to a flip chip bonding apparatus using an anisotropic conductive film and a bonding method.

Generally, the semiconductor package includes a resin sealing package, a TCP (Tape Carrier Package) package, a glass sealing package, and a metal sealing package depending on the type thereof. Such a semiconductor package is classified into an insertion type and a surface mount technology (SMT) type according to a mounting method. Typical examples of the insertion type are a dual in-line package (DIP) and a pin grid array (PGA) Representative examples of the mounting type include QFP (Quad Flat Package), PLCC (Plastic Leaded Chip Carrier), CLCC (Ceramic Leaded Chip Carrier), and BGA (Ball Grid Array).

In recent years, in order to increase the degree of mounting parts of a printed circuit board in accordance with miniaturization of electronic products, a surface mount type semiconductor package is widely used rather than an insertion type semiconductor package. In contrast, the semiconductor chip is gradually increased in performance, It is technically difficult to narrow the distance between the pin and the pin to be less than a predetermined value. Therefore, a package has to be enlarged in order to accommodate all the pins. Thus, flip chip bonding has been developed to overcome such a problem .

1 schematically shows a flip chip bonding structure.

Referring to the drawings, flip chip bonding refers to bonding a bump 4 to a surface of a chip without separately packaging such as encapsulating the semiconductor chip 2 with an encapsulating material, 6).

In recent years, anisotropic conductive film (Anisotropic Conductive Film) 8 and anisotropic conductive adhesive (Anisotropic Conductive Film) have been used as an adhesive resin for bonding the semiconductor chip 2 and the sub strap 6, Adhesive.

The anisotropic conductive film 8 (hereinafter referred to as ACF) is formed by coating a polymer with several hundreds of metallic particles 8a having a diameter of about 5 탆 inside a thin adhesive resin of several to several tens of microunits. 8), the polymer coated on the metallic lattice is melted due to heat in the portion pressed between the conductors at the time of thermocompression, thereby maintaining the energized state, and the remaining portions remain in the insulated state. This helps to maintain a more reliable connection between the chip 2 and the sub-strap 6.

However, in order to bond the flip chip to a substrate such as a mother board, the unit film corresponding to the chip packaging needs to be cut from the ACF 8 before the flip chip is bonded, The process time is delayed and the workability is deteriorated and the productivity is lowered.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a flip chip bonding method and a flip chip bonding method, An object of the present invention is to provide a flip chip bonding method using an anisotropic conductive film and a bonding apparatus.

According to an aspect of the present invention, there is provided an anisotropic conductive film comprising: an anisotropic conductive film;

Wherein the pick-up tool picking up the chip with the bump is placed on the chip pad of the supertor having the anisotropic conductive film on the surface thereof;

Separating the unit film necessary for chip mounting from the anisotropic conductive film;

And a step of thermocompression bonding the chip and the unit film to the chip pads of the superty while the separated unit film is attached to the bottom surface of the chip, the method comprising the steps of: providing a flip chip bonding method using the anisotropic conductive film; do.

The present invention also provides a semiconductor device, comprising: a substrate on which a semiconductor chip is mounted;

A pick-up tool that moves the semiconductor chip with the bumps attached thereto and mounts the semiconductor chip on the substrate;

An anisotropic conductive film positioned between the supertwand and the pick-up tool to which the chip is attached;

And film separating means for separating as much unit film as necessary for chip mounting from the anisotropic conductive film, wherein the pick-up tool thermally compresses the chips to the supersatellite while separating as much unit film as necessary for the supersatellite packaging A flip chip bonding apparatus using an anisotropic conductive film is provided.

Hereinafter, the structure and method of the present invention will be described in detail with reference to the accompanying drawings. Prior to describing the present invention, for the sake of avoiding duplication of the description, portions corresponding to those of the prior art will be cited as they are.                     

2 is a schematic view showing a flip chip bonding apparatus using an anisotropic conductive film (hereinafter, ACF) according to the present invention.

Referring to FIG. 1, the flip chip bonding apparatus includes a mount 10 having a flat upper surface portion, a supporter 6 mounted on the mount 10, and a semiconductor chip 2 having bumps 4 formed thereon. And a pick-up tool 20 for moving the pick-up tool 20 and mounting it on the supporter 6.

An ACF 8 is mounted between the pick-up tool 20 and the sub-strut 6 on which the semiconductor chip is mounted, that is, the surface portion of the sub-strut 6.

The mount is a means for mounting the supersatta 6, and is installed so as to apply heat of a constant temperature like a heater block, and fixes the supersat 6.

The sub-strap 6 is provided with a panel-type circuit pattern substrate (not shown) for connecting an electric signal input / output from an integrated circuit of the semiconductor chip 2, such as a printed circuit board or a motherboard, to various additional devices of the sub- .

The pick-up tool 20 is a means for transferring an individual semiconductor chip 2 formed with a bump 4 on a wafer or the like and mounting the semiconductor chip 2 on a chip pad of the supporter 6, Or the back surface of the chip 2, and then moves on the supertor 6 to which the semiconductor chip is to be mounted and descends to bond the chip 2.

The pick-up tool 20 shown in the embodiment of the present invention has a punch 30 formed on the outer periphery thereof and the punch 30 is separated from the wide spread ACF 8 by a unit film necessary for chip mounting Is used as the film separating means (30).

As described in the background art, the ACF (8) is formed by coating a polymer with several hundreds of metallic tablets (8a) having a diameter of about 5 탆 inside a thin adhesive resin of several to several tens of microunits, And is a non-conductive film having a certain electrical conductivity when the metallic tablets 8a are arranged in a line.

The conductive particles 8a of the ACF 8 (anisotropic conductive film) are various kinds. For example, a polymer-based core may be coated with Ni / Au, a polymer may be coated with an insulating layer on the coated outer surface, or may be a single metal particle such as Ni, or a metal- Various ACFs can be applied, such as coated with an insulating layer on the side surface.

In addition, the shape may have a rounded spherical shape as shown in the drawing, may be a rugged shape or a rod shape, and the sizes may vary.

As shown in the drawing, the ACF 8 can be divided into a layer having a conductive lattice 8a and a nonconductive layer. The ACF 8 can be simply placed on the surface of the subcutaneous layer 6 or can be pre- have.

Hereinafter, a flip chip bonding method using the anisotropic conductive film 8 of the present invention will be described in more detail with reference to FIGS. 3 to 5. FIG.

3 is a schematic view showing a state in which the semiconductor chip 2 on which the bumps 4 are formed is transferred onto the supporter 6 on which the ACF 8 is placed by vacuum picking up the pickup tool 20.

Referring to the drawings, the semiconductor chip 2 has bumps 4 formed on its surface. The bump 4 is a lead-out terminal for inputting and outputting an electric signal of the integrated circuit, and is usually formed by a wire bonding method. The bumps are divided into gold plated bumps, gold stud bumps, electroless Ni / Au bumps, and the like according to the formation method. In the present invention, Can be applied.

Such a semiconductor chip 2 is manufactured in the state of a wafer or is manufactured in an individual chip state. A chip on which the bump 4 is formed is picked up by the pick-up tool 20 in a vacuum adsorption manner or the like, Move it over the mount (10).

A punch 30 as a film separating means is provided on the outer periphery of the pick-up tool 20 so that the pick-up tool 20 can be moved up and down while the punch 30 and the pick-up tool 20 are assembled and installed have.

When the pick-up tool 20 picks up the semiconductor chip, the pick-up tool 20 descends below the punch tip 32 and picks up the semiconductor chip 2. When the pick-up tool 20 moves, the pick-up tool 20 moves upward above the punch tip 32.

4 shows a state in which the pickup tool 20 moved above the supertor 6 partially separates the ACF 8 with the punch 30 while descending to the chip pad 6a to which the chip 2 is to be bonded Fig.

4, the punch 30 installed on the outer periphery of the end of the pick-up tool 20 cuts the ACF 8 in half or half, while the pick-up tool 20 descends. The punch 30 has a substantially rectangular cross section in accordance with the shape of the chip 2, and the outer circumferential tip portion is formed in a sharp shape, so that the ACF 8 is cut into a unit film necessary for chip mounting.

5 is a sectional view showing a step in which the ACF 8 is cut into a unit film 82 by the punch 30 and the pickup tool 20 compresses the unit film and the chip together with the cutting film 20 to the substrate 6 together.

As shown in the drawing, the punch 30 is fixed while pressing down the chip 2 on which the bump 4 is formed while the pickup tool 20 inside is lowered, and the unit film 82 located on the bottom of the chip is pressed do. At this time, the mount 10 located on the bottom surface of the sub strut 6 applies heat to the sub strut 6 to improve the bonding force of the ACF 8.

At this time, when the ACF 8 is bonded to the semiconductor chip 2, a thermal compression bonding method is used. In this case, the heat is raised to a predetermined temperature or higher so that the film 82 becomes a fluid mucus material, In order to fill the gap between the supporter 2 and the suppleate pad 6a, The unit film 82 under pressure by the pressing of the pick-up tool 20 is arranged in a line between the connection terminals of the bumps 4 and the chip pads 6a in accordance with the characteristics thereof, So that the semiconductor chip 2 and the sub strap 6 are electrically connected.

The flip chip bonding method using the above-described anisotropic conductive film 8 (ACF (8)) will be described more simply.

In the first step, the ACF 8 is placed on the suplet 6. In this case, it may be simply placed, but it is also preferable to pre-bond with a slight thermocompression.

In the second step, the semiconductor chip 2 on which the bumps 4 are adhered is picked up individually by the pick-up tool 20 and moved on the supporter 6 on which the ACF 8 is mounted.

In the third step, the pick-up tool 20 to which the chip 2 is attached is lowered. First, the ACF 8 is separated into a unit film 82 necessary for mounting the chip 2.

In the fourth step, the semiconductor chip with the unit film attached thereto is down-compressed while the pick-up tool 20 is lowered, and the ACF 8 unit film is adhered to the supporter 6 by applying heat to the supersat 6.

When the flip chip is bonded as described above, the process of separating and cutting the ACF 8 by the unit film 82 separately and pre-bonding the substrate 6 to the supporter 6 can be omitted, thereby shortening the process time and improving the productivity .

The ACF 8 shown in the embodiment of the present invention can use a simple film structure cut by the punch 30 or another structure of the ACF 8 to improve the effect of the present invention.

6A and 6B are plan views showing other embodiments of the ACF 8 according to the present invention.

6A, the ACF 8 is formed with an oil chamber 80 in which a plurality of holes h are formed on the outer circumference of the unit film 82a so as to facilitate individualization of the unit film 82. FIG. The oil chamber 80 is designed to facilitate separation of the unit film 82a from the ACF 8. Even if the pickup tool 20 is not provided with a separate punch 30, The unit film 82a can be separated from the ACF 8 by the speed and the pressing force.

6B shows another embodiment of the ACF 8 in which a slot-shaped hole s is formed on the outer periphery of the unit film 82b and a rectangular hole is formed at the square edge of the unit film 82b in the ACF 8 state A tie bar 84 is formed.

Only the tie bars 84 need to be cut off when the unit film 82b is separated from the ACF 8 so that the pickup tool 20 does not have a separate punch 30 like the ACF 8 of FIG. There is an advantage that it can be easily separated into the unit film 82b.

When an anisotropic conductive film is used to bond a flip chip, the anisotropic conductive film is cut into a unit film separately, and the chip is mounted in a state in which the ACF is directly bonded to the substrate without prebonding to the substrate. And productivity is improved.

Claims (5)

Depositing an anisotropic conductive film on the substrate; Wherein the pick-up tool picking up the chip on which the bump is formed is placed on a surface of the chip pad of the substrate on which the anisotropic conductive film is provided; Separating the unit film necessary for chip mounting from the anisotropic conductive film; And a step of thermocomposing the chip and the unit film on the chip pads of the supporter in a state where the separated unit film is attached to the bottom surface of the chip. A substrate on which a semiconductor chip is mounted; A pick-up tool for moving the semiconductor chip on which bumps are formed and mounting the semiconductor chip on the substrate; An anisotropic conductive film positioned between the supertwand and the pick-up tool to which the chip is attached; And film separating means for separating as much unit film as necessary for chip mounting from the anisotropic conductive film, wherein the pick-up tool thermally compresses the chips to the supersatellite while separating as much unit film as necessary for the supersatellite packaging Flip chip bonding apparatus using an anisotropic conductive film. 3. The method of claim 2, Wherein the film separating means is a punch having a sharp tip at an end corresponding to the size of the unit film. 3. The method of claim 2, Wherein an anisotropic conductive film is formed on the outer periphery of the unit film so as to have a size corresponding to the unit film so that the unit film can be separated by the lowering of the pick-up tool. 5. The method of claim 4, Wherein the flow-through is a plurality of circular or slot-like holes.

Images