JP2001135925A - Supplying method and supplying device for flux - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flux supply device as well as flux supply method where flux is supplied at high positional accuracy and high-accuracy transfer amount. SOLUTION: For a flux supply device for supplying a flux 3 to an electrode pad of a substrate, a flux supply pallet 1, where a flux supply hole 2 is formed at a position corresponding to the electrode pad of substrate, and a flux transfer plate 5 where a projection 6 is formed corresponding to the flux supply hole 2, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming bumps in flip chip connection and ball grid array, and more particularly to an apparatus and method for supplying a flux when transferring solder balls to a semiconductor chip, a wiring board, or the like. About.

[0002]

2. Description of the Related Art A method of supplying a flux for forming a solder bump electrode such as a flip chip, a chip size package (CSP), a ball grid array (BGA) by using a solder ball includes a semiconductor chip and a wiring board. , A method of transferring to an electrode pad using a jig, a method of directly transferring to a solder ball, and the like.

Although the printing method is already widely used, it is difficult to manufacture a metal mask when the pad pitch is narrow.

[0004] A conventional method of transferring to an electrode pad using a jig is described in, for example, JP-A-9-82719 (hereinafter, referred to as a first conventional technique).

Referring to FIG. 5, a first conventional transfer method will be described.

As shown in FIGS. 5 (a) and 5 (b), a tip end of a flux transfer substrate 10 having a projection 11 corresponding to an electrode pad 16 of a printed substrate 15 to be transferred is immersed in a flux bath 12.

[0007] Then, as shown in FIG. 5 (c), the flux 13 is attached to the tip of the projection 11.

Next, as shown in FIG. 5D, the flux transfer plate 10 is moved onto the printed circuit board 15.

After that, as shown in FIGS. 5E and 5F, the flux 14 is transferred to the electrode pads 16 of the printed circuit board 15.

Subsequently, as shown in FIGS. 5 (g), 5 (h) and 5 (i), the flux 1 to which the solder ball 20 has been transferred is applied.
7

In this way, bumps 21 are formed on the electrode pads 16 as shown in FIG.

Next, as a method of direct transfer to a solder ball, for example, it is described in Japanese Patent Application Laid-Open No. 11-54516 (hereinafter referred to as a second conventional technique).

Referring to FIG. 6, a second prior art will be described.

As shown in FIG. 6, a transfer device according to the second prior art includes a ball array substrate 23 for attracting and holding metal balls B at a predetermined array position, and a flux at a position corresponding to the array position of the metal balls B. A flux supply means 24 having a supply hole 26a and a drive mechanism (not shown) capable of positioning and moving the ball array substrate 23 are provided.

With such a configuration, when supplying the flux F, the flux F is supplied for each metal ball B at the same position as the arrangement position of the metal balls B. The flux F is pressurized to swell appropriately from the flux supply hole 26a. Thereby, an appropriate amount of the flux F can be appropriately applied only to the tip portion of the metal ball B.

[0016]

In the case of the first prior art, when the projections of the transfer substrate are formed at a narrow pitch corresponding to the semiconductor chips or the wiring substrates having the narrow pitches of the electrode pads, When the tip is immersed in a flux bath and the flux is transferred, the flux may enter between adjacent projections, and the flux may adhere to a plurality of adjacent projections.

In order to easily immerse only the tips of the projections in the flux bath, the height of the projections needs to be 200 μm or more, preferably 500 μm or more.

In the first prior art, as an example, a columnar shape having a cross-sectional diameter of 50 μm and a height of 500 μm is shown. To manufacture such a jig having a high aspect ratio, In practice it is very difficult and costly.

In the case of the second prior art, the flux does not come into direct contact with the ball array substrate. However, even when the flux is transferred to the ball, the flux is fixed to the ball array hole of the ball array substrate by vacuum suction. Therefore, there is a possibility that the flux goes up along the ball and adheres to the ball arrangement hole. Alternatively, the flux may be sucked into the vacuum suction device, causing a problem.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a flux supply device capable of supplying a flux with high positional accuracy and a transfer amount with high accuracy. An object of the present invention is to provide an apparatus and a flux supply method.

[0021]

According to the present invention, there is provided a flux supply apparatus for supplying a flux to an electrode pad of a substrate, wherein a flux supply hole is provided at a position corresponding to the electrode pad of the substrate. And a flux transfer plate in which projections are formed corresponding to the flux supply holes.

Here, the flux filled in the flux supply holes formed in the flux supply pallet is
The flux is attached to the projections by making contact with the projections formed on the flux transfer plate.

The filling of the flux supply holes with the flux is preferably performed using a squeegee.

Alternatively, a flux supply device having a through hole provided corresponding to the flux supply hole is connected to the flux supply pallet, and the flux is filled into the flux supply hole via the through hole. You may do it.

It is preferable that a flux adsorbing layer for adsorbing the flux is provided at the tip of the projection formed on the flux transfer plate. The flux adsorption layer is made of, for example, a porous material.

Alternatively, the flux adsorption layer may be formed by forming irregularities at the tip of the projection.

Preferably, the flux supply pallet is made of a silicon substrate, and the flux supply holes are formed by anisotropic etching or isotropic etching.

Preferably, the flux transfer plate is made of a silicon substrate, and the projections are formed by anisotropic etching or isotropic etching.

It is preferable that the flux transfer plate is made of an elastic resin.

In this case, the resin having elasticity is desirably selected at least from a silicone resin, a Teflon resin, a butadiene resin, a fluorine resin and a polyurethane resin.

Further, according to the present invention, there is provided a flux supply method for supplying a flux to an electrode pad of a substrate, wherein a flux supply pallet having a flux supply hole formed at a position corresponding to the electrode pad of the substrate; Prepare a flux transfer plate with protrusions corresponding to the holes, fill the flux supply holes with flux, and align the flux transfer plate and the flux supply pallet so that the flux supply holes and the protrusions face each other. Then, the flux filled in the flux supply holes formed on the flux supply pallet is brought into contact with the projections formed on the flux transfer plate, whereby the flux is attached to the projections. To be transferred to

The filling of the flux supply holes with the flux is preferably performed using a squeegee.

Alternatively, the filling of the flux supply holes with the flux may be performed by pressurization using a flux supply device.

[0034]

According to the present invention, flip chip, CSP, BGA
In a flux supply device and method for supplying flux when forming solder bump electrodes using solder balls, a hole having a uniform size is formed in a silicon substrate by etching, and the hole is filled with a flux using a squeegee or the like. Let it.

Further, a flux is adhered to a projection of a flux transfer plate made of silicon, resin, or the like, and is transferred and supplied to an electrode pad of a semiconductor chip or a wiring board.

As a result, it becomes possible to supply the flux with high positional accuracy and the transfer amount with high accuracy. In particular, when the flux transfer plate is manufactured by etching a silicon substrate, the positional accuracy and the amount of flux can be controlled with higher accuracy.

[0037]

Embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) A first embodiment of the present invention will be described with reference to FIG.

Here, the flux supply pallet 1 is made of a silicon substrate, and the flux supply holes 2 are formed on one side of the silicon substrate by an anisotropic etching method. Therefore, the flux supply hole 2 has a quadrangular pyramid shape.

The flux supply hole 2 does not have to be a perfect quadrangular pyramid, and its bottom may be flat or rounded.

First, as shown in FIG. 1A, the flux 3 is filled in the flux supply hole 2 using the squeegee 4.

Next, as shown in FIG. 1 (b), the flux transfer plate 5 is aligned with the flux supply pallet 1, lowered and brought into contact with the projections 6, and then raised. As a result, as shown in FIG.
The flux 3 is adhered to the projection 6.

Thereafter, the flux 3 adhered to the tip of the projection 6 is transferred and supplied to an electrode pad (not shown) of a semiconductor chip or a wiring board.

As a result, the amount of flux adhering to the tip of the projection 6 can be made uniform with high precision.
The amount of flux transferred to the electrode pads of the semiconductor chip or the wiring board can also be accurately and uniformly made.

The flux transfer plate 5 is made of a silicon substrate, and the projections 6 are formed by an anisotropic etching method. Note that the apex of the protrusion 6 may be pointed, flat, or rounded.

In the case of this method, the flux supply pallet 1 can be manufactured easily and at low cost even with a narrow pitch pattern with a uniform size of the flux supply holes 2 and good positional accuracy. Further, the flux transfer plate 5 can be manufactured easily and at low cost with high accuracy even in a narrow pitch pattern, in which the projections 6 have a uniform size and good positional accuracy.

Although the projections 6 and the flux supply holes 2 are formed by the anisotropic etching method, they may be formed by other methods as long as they can be manufactured with high precision, such as an isotropic etching method.

Although the flux transfer plate 5 and the flux supply pallet 1 are made of silicon,
Other materials such as a silicone resin may be used as long as they can be manufactured with high accuracy. For example, if a silicon substrate having holes formed by anisotropic etching or isotropic etching is used and molded with a silicone resin or the like, a flux transfer plate with high accuracy in the size and position of the protrusions can be obtained. Can be made.

Here, it is desirable that the flux transfer plate 5 is formed of an elastic resin. For example, as the resin having elasticity, a silicone resin, a Teflon resin, a butadiene resin, a fluorine resin, a polyurethane resin, or the like is preferable.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIG.

In FIG. 2, the flux supply pallet 1
Is formed with a flux supply hole 2 having uniform size and high positional accuracy by performing anisotropic etching on both sides of a silicon substrate.

The flux supply pallet 1 is connected to a flux supply device 7 so that the flux 3 is supplied from a flux supply source (not shown).

As shown in FIG. 2A, the flux 3 passes through the flux supply hole (through-hole) 8 by pressurization and is filled in the flux supply hole 2.

After aligning the projections 6 of the flux transfer plate 5 manufactured in the same manner as in the first embodiment with the flux supply holes 2, the flux transfer plate 5 is lowered as shown in FIG. Then, the protrusion 6 is brought into contact with the flux 3 in the flux supply hole 2.

Thereafter, when the flux transfer plate 5 is raised, a state in which a certain amount of the flux 3 adheres only to the tip of the projection 6 is obtained as shown in FIG.

Subsequently, as in the first embodiment, the flux 3 attached to the tip of the projection 6 is transferred to a semiconductor chip or an electrode pad (not shown) of a wiring board and supplied.

Although the projections 6 and the flux supply holes 2 are formed by the anisotropic etching method, other methods such as an isotropic etching method may be used as long as they can be accurately manufactured. Further, although the flux transfer plate 5 and the flux supply pallet 1 are made of silicon, other materials such as a silicone resin may be used as long as they can be manufactured with high accuracy. For example, if a silicon substrate with holes formed by anisotropic etching or isotropic etching is used and molded with silicone resin or the like, a flux transfer plate with high accuracy in the size and position of the protrusions is manufactured. it can.

Here, the flux transfer plate 5 is desirably formed of an elastic resin. For example, as the resin having elasticity, a silicone resin, a Teflon resin, a butadiene resin, a fluorine resin, a polyurethane resin, or the like is preferable.

(Third Embodiment) A third embodiment of the present invention will be described with reference to FIG.

In the same manner as in the second embodiment, in FIG. 2A, a flux supply hole 2 is formed by performing anisotropic etching on both sides of a silicon substrate, and a flux supply pallet 1 is obtained.

The opening is formed in accordance with the shape and size of the projection 6. Projection 6 of flux transfer plate 5
After aligning the flux supply holes 2 with each other, FIG.
As shown in the figure, the flux transfer plate 5 is lowered,
The protrusion 6 is brought into contact with the flux 3 in the flux supply hole 2.

At this time, as shown in an enlarged view of a portion A in FIG. 2B shown in FIG. 3, the projection 6 and the flux supply hole 2 are aligned. By doing so, the area of the projections 6 that come into contact with the flux 3 can be accurately made constant, so that the amount of the flux 3 adhering to the projections 6 can be accurately controlled.

At this time, it is desirable to apply pressure in the direction of the projection 6 from below. Thereafter, when the pressure is removed and the flux transfer plate 5 is raised, a state in which a certain amount of the flux 3 adheres only to the tip of the protrusion 6 is obtained as shown in FIG.

Next, similarly to the first and second embodiments, the flux 3 attached to the tip of the projection 6 is transferred to an electrode pad (not shown) of a semiconductor chip or a wiring board and supplied.

The protrusion 6 and the flux supply hole a2
May be manufactured by a method other than the anisotropic etching method. Further, the flux transfer plate 5 and the flux supply pallet 1 may be made of a material such as resin other than silicon.

(Fourth Embodiment) A fourth embodiment of the present invention will be described with reference to FIG.

As shown in FIG. 4, a flux adsorption layer 9 is formed at the tip of the projection 6 of the flux transfer plate 5. The flux adsorption layer 9 is made of, for example, a porous material.

Since the liquid flux enters into a large number of fine pores in the porous material, the flux adsorbing layer 9 made of the porous material can more reliably adhere the flux.

Alternatively, the same effect can be obtained by forming fine irregularities by roughening the tip of the projection 6 as the flux adsorption layer 9.

It is to be noted that other materials to which the flux easily adheres may be used.

[0071]

According to the present invention, flip chip, CS
In a jig and a method for supplying flux when forming solder bump electrodes such as P and BGA using solder balls, a hole having a uniform size is formed in a silicon substrate by etching, and a flux is applied to the hole with a squeegee or the like. The flux is applied to the projections of the flux transfer plate, and the flux is transferred to and supplied to the electrode pads of the semiconductor chip and the wiring board, so that the flux can be supplied with high positional accuracy and transfer amount.

In particular, when the flux transfer plate is manufactured by forming protrusions on a silicon substrate by anisotropic etching, the positional accuracy and the flux amount can be transferred and supplied with higher accuracy.

Further, since the method is not a method of directly transferring the flux to the solder balls as in the second prior art, there is no problem caused by the suction of the flux into a vacuum pump or the like.

Further, unlike the first prior art, the flux does not adhere between the adjacent projections of the flux transfer plate, so that the flux can be supplied only to the electrode pads of the semiconductor chip and the wiring board. As a result, there is no short circuit between adjacent solder bump electrodes.

Further, since only the required amount of flux transfer can be supplied with high accuracy, the cleaning performance is improved.

[Brief description of the drawings]

FIG. 1 is a process chart for explaining a flux supply method according to a first embodiment of the present invention.

FIG. 2 is a process diagram illustrating a flux supply method according to a second embodiment of the present invention.

FIG. 3 is a process chart for explaining a flux supply method according to a third embodiment of the present invention.

FIG. 4 is a process chart for explaining a flux supply method according to a fourth embodiment of the present invention.

FIG. 5 is a process diagram illustrating a flux supply method according to a first conventional technique.

FIG. 6 is a diagram for explaining a flux supply method according to a second conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flux supply pallet 2 Flux supply hole 3 Flux 4 Squeegee 5 Flux transfer plate 6 Projection 7 Flux supply device 8 Flux supply hole (through hole) 9 Flux adsorption layer 10 Flux transfer substrate 11 Projection 12 Flux bath 13 Flux 14 Adhered to projections Flux 15 Printed board 16 Electrode pad 17 Flux transferred to electrode 18 Array substrate 19 Adsorption hole 20 Ball 21 Bump 22 Array head 23 Ball array substrate 23a Ball array hole 24 Flux supply means 25 Flux container 26 Substrate 26a Flux supply hole 27 Piston

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Naoji Senba 5-7-1 Shiba, Minato-ku, Tokyo Inside NEC Corporation (72) Inventor Yuzo Shimada 5-7-1 Shiba, Minato-ku, Tokyo Japan Inside Electric Company (72) Inventor Takumi Yamamoto 348 Oshima-cho, Hamamatsu-shi, Shizuoka Japan Inside Japan E-M Corporation (72) Inventor Kazuhiko Futami 348 Oshima-cho, Hamamatsu-shi, Shizuoka Japan E-M shares In-company (72) Inventor Akira Hatase 348 Oshima-cho, Hamamatsu-shi, Shizuoka Japan F-term (reference) in Japan IM Co., Ltd. 5E319 CD22

Claims (14)

[Claims] 1. A flux supply device for supplying flux to an electrode pad of a substrate, comprising: a flux supply pallet having a flux supply hole formed at a position corresponding to the electrode pad of the substrate; And a flux transfer plate having projections formed thereon. 2. The method according to claim 1, wherein a flux filled in a flux supply hole formed in the flux supply pallet is brought into contact with a projection formed in the flux transfer plate, thereby causing the flux to adhere to the projection. Item 7. A flux supply device according to Item 1. 3. The flux supply device according to claim 2, wherein the filling of the flux supply hole with the flux is performed using a squeegee. 4. A flux supply device having a through hole provided corresponding to the flux supply hole is connected to the flux supply pallet, and the flux is charged into the flux supply hole via the through hole. The flux supply device according to claim 2, wherein the flux supply is performed. 5. The flux supply device according to claim 1, wherein a flux adsorption layer for adsorbing the flux is provided at a tip of the projection formed on the flux transfer plate. 6. The flux supply device according to claim 5, wherein the flux adsorption layer is made of a porous material. 7. The flux supply device according to claim 5, wherein the flux adsorption layer is formed by forming irregularities at the tip of the projection. 8. The flux supply device according to claim 1, wherein the flux supply pallet is made of a silicon substrate, and the flux supply holes are formed by anisotropic etching or isotropic etching. 9. The flux supply device according to claim 1, wherein said flux transfer plate is made of a silicon substrate, and said projections are formed by anisotropic etching or isotropic etching. 10. The flux supply device according to claim 1, wherein the flux transfer plate is made of an elastic resin. 11. The flux supply device according to claim 10, wherein the resin having elasticity is selected from at least a silicone resin, a Teflon resin, a butadiene resin, a fluorine resin and a polyurethane resin. 12. A flux supply method for supplying flux to an electrode pad of a substrate, comprising: a flux supply pallet having a flux supply hole formed at a position corresponding to the electrode pad of the substrate; Preparing a flux transfer plate having protrusions formed thereon, filling the flux supply holes with a flux, aligning the flux transfer plate and the flux supply pallet such that the flux supply holes and the protrusions face each other, The flux filled in the flux supply holes formed on the flux supply pallet is brought into contact with the projections formed on the flux transfer plate to attach the flux to the projections. A flash that is transferred to an electrode pad. To supply methods. 13. The flux supply method according to claim 12, wherein the filling of the flux supply holes with the flux is performed using a squeegee. 14. The flux supply method according to claim 12, wherein the filling of the flux supply hole with the flux is performed by pressurization using a flux supply device.