JPH10335810A - Reworking equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a reworking equipment which can remove a package component with bumps, such as a BGA by a relatively simple method and which allows the reuse of the removed component. SOLUTION: In a reworking equipment which, being provided with a heating equipment and a suction jig for a component 2, heats a substrate 1 on which the component 2 mounted by means of the heating equipment to melt solder and holds the component 2 mounted on the substrate by means of the component suction jig and then removes if from on the substrate 1, molten solder bumps 2-1 located on a junction face between the substrate 1 and the component 2 are cut at their substrate sides, by a cutting section (string) 3-1 of a floss-type tool 3 having the thread-like cutting section (string) 3-1 after the solder has melted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rework apparatus for removing a soldered element, and more particularly to an improvement in a rework apparatus for an LSI having a solder bump such as a BGA type CSP package.

[0002]

2. Description of the Related Art In a conventional rework apparatus, defective elements are
The operation of removing an LSI element with a solder bump once soldered for the purpose of checking a failure of a board, a failure of another component, a wiring, and the like will be described with reference to FIGS. 5 and 6, reference numeral 11 denotes a mother board on which an LSI element having solder bumps is mounted, and 12 denotes a BSA as an example of an LSI element having solder bumps.
Package parts, 14 is a heating device of a rework device, 15
Is a suction jig of the rework device.

Conventionally, as shown in FIGS. 5 and 6, a heating device 14 of a reworking device heats the upper and lower surfaces of a substrate 11 so that the CSP package component 12 is heated in a molten state.
Is held by the suction jig 15 or the holding jig of the rework apparatus, and is removed by mechanical force.

However, in such a method, a so-called CS
PGA (Chip Size Package), BGA (Ball Grid Ar
In the case of components such as LSI devices with solder bumps such as ray), the bumps are often removed and remain on the mother board 11, so that the removed components cannot be reused and almost new components must be replaced. There was an inconvenience of becoming.

Here, CSP and BGA will be briefly described. It is known that the number of terminals of a logic device is represented by an exponential function with respect to the number of gates mounted on a chip. The relational expression representing this is an expression called the Rent rule shown below. Np = αNgβ where Np: number of terminals of the device α: coefficient determined by the type of device Ng: number of gates in the chip β: value determined by the type of device and is called Rent index.

As the number of gates mounted on the gate device increases year by year, the number of terminals naturally increases. It is believed that devices with more than 1000 terminals will appear by 2000. Due to the increased number of terminals, the package size of the existing package increases, the occupied area increases, and the merits of highly integrated functions are reduced by half.
In particular, when the number of terminals exceeds a few hundred, it is not possible to catch up with just narrowing the outer leads of the package. One method to solve this is a CSP package such as a BGA package.

The CSP is a package type close to the original chip size of the LSI. For example, 160 pin ASIC
In the case of (Application Specific Integrated Circuit), the area occupied by the package can be reduced to about 1/10 compared to a general package QFP (QuadFlat Package), and the mounting density can be reduced. There are benefits that can be raised. In addition, unlike the case of the bare chip, there is an advantage that the LSI maker can assure the quality and ship the product in the same manner as a normal package product.

The external terminals of the CSP include, for example, BGA and LGA (Land Grid Array). These are package shapes in which terminal contacts are provided in a two-dimensional area. By doing so, it is possible to avoid narrowing the pitch while keeping the package size small, thereby avoiding restrictions on package manufacturing. be able to.

For example, in the case of a two-dimensional area terminal arrangement, 10,000 I / Os can be easily obtained simply by forming a 100.times.100 matrix in a package shape of about 10 cm square. Among the CSPs, the LGA is a package having no leads and only pads, and is mounted on a printed circuit board via a connector.

On the other hand, the BGA has an LSI bare chip mounted on a small square printed circuit board, and two-dimensionally semi-spherical or spherical terminals (bumps) are arranged on the lower surface. In this case, the terminals (bumps) are often soldered directly to the substrate using solder. A package with about 225 to 350 pins has already been put into practical use. LSI with many terminals
However, there is an advantage that the package does not need to be so large. Furthermore, the electrical characteristics of the connection are low resistance, low capacitance,
It also has the advantage of low inductance.

However, the elements connected in such an area are connected only in the periphery because the connection portion is hidden by the shadow.
There is a problem in that it is not possible to visually inspect the good / bad soldering compared to FP, etc.
There is a problem that rework takes time.

FIG. 7 shows a cross-sectional shape of such a BGA, and FIG. 8 schematically shows an example of terminal (bump) arrangement on the back surface. In FIG. 7, 21 is an IC chip, 22 is a solder mask, 23 is an epoxy substrate, 24
Is a through-hole pier, 25 is a solder terminal (bump), 2
6 is a copper wiring, 27 is a wiring wire, and 28 is a molding material.

A printed epoxy board 23 is used as a package material, and the IC chip 21 is molded with a molding material 28 after wire bonding. The wiring from the IC chip 21 is guided to a solder terminal (bump) 25 provided on the back surface of the epoxy substrate 23 via a wiring 27 and a through-hole pier 24. The solder terminals (bumps) 25 are used to perform solder mounting on the substrate.

FIG. 9 shows a cross-sectional structure of such a solder terminal (bump). In FIG. 9, 31 is a solder, 32 is a barrier metal, 33 is a silicon oxide insulating film SiO2, 34
Is an aluminum pad, and 35 is a silicon layer.
The structure of the bumps is Ni or Pd to obtain good electrical contact with the aluminum pad 34, to form a bonding layer such as Ti or Cr, or to prevent the formation of intermetallic compounds.
It is made of solder via a barrier metal 32 made of a diffusion prevention layer such as a metal.

By the way, terminals (bumps) having such a configuration are used.
If there are many, if the solder of the bumps is removed on the board side when trying to rework the parts by the conventional method,
As it is, re-soldering becomes impossible, and replenishment of the solder is practically difficult, making it impossible to reuse the removed parts.

[0016]

As described above, when a conventional reworking device is used to rework a model with bumps such as a BGA of a CSP package, the bumps are often stuck to the substrate side and removed. Therefore, there is a problem that the reworked parts cannot be used.

The present invention solves this problem, and realizes a rework apparatus capable of easily removing a package component having a bump such as a BGA by a relatively simple method and reusing the removed component. As an issue.

[0018]

To achieve the above object, the present invention comprises a heating means and a component holding means,
In a reworking apparatus for heating a substrate on which components are mounted by the heating means to melt the solder and holding the components mounted by the component holding means and removing the solder from the substrate, a solder connection surface separation having a thread-like cut portion is provided. The solder connection surface separating means cuts the board side of the melted solder at the joint surface between the board and the component after the solder is melted by the thread-shaped cutting portion.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a rework apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an explanatory diagram showing the basic concept of the operation of the rework apparatus according to one embodiment of the present invention. In FIG. 1, 1 is a mother board, 2
Is a BGA package component, 2-1 is a terminal (bump), 3
Denotes a string of the goose-shaped tool 3, and 3-1 denotes a string of the goose-shaped tool 3. The operation of this embodiment will be described with reference to FIG.

When the BGA package component 2 is to be removed from the surface of the motherboard 1, the terminals (bumps) 2-1 are heated by a heating device (not shown in FIG. 1) to melt the solder. Then, the needle-shaped tool 3 is moved, and the string (3-1) of the tooth-shaped tool 3 is used to make a terminal (bump).
2-1 and the pattern on the mother substrate 1 are cut.

In this way, the solder is cut off at the cut portion, and the B mounted on the mother board 1 is removed.
When separating the GA package component 2, the terminals (bumps)
The portion 2-1 does not adhere to the substrate side, and the terminal (bump) 2-1 is not likely to be peeled off.
Therefore, the BGA package component 2 removed from the substrate 1 can be reused.

The operation of the rework apparatus according to this embodiment of the present invention will be described in more detail with reference to FIGS. 2 and 3, 1 is a mother board, 2 is a BGA package component, 2-1 is a terminal (bump), 3 is a goose-shaped tool, 3-1 is a string of a goose-shaped tool 3, 4 is a rework. The heating device 5 of the device is a suction jig of the rework device. In FIGS. 2 and 3, the same functions as those in FIG. 1 are given the same numbers for convenience.

In FIG. 2, the mother board 1 from which the mounted BGA package component 2 is to be removed is set in a rework device, and the BGA package component 2 is fixed by a suction jig 5 as in the conventional case.

Next, in this state, the heating device 4 is operated to send hot air to the mother substrate 1 to melt the solder. When the solder used is 3Bi low melting point solder made of bismuth and tin, the temperature of the solder joint is 175 ° C. to 185 °.
Heat to a temperature in the range of C.

Subsequently, the string 3 of the needle-shaped tool 3 is moved on the surface of the mother board 1 by moving the needle-shaped tool 3 above the mother substrate 1, and the lower surface of the terminal (bump) 2-1 is moved. The solder is cut on the mother board 1 side. Once the solder is cut in this way, an oxide film is formed on the surface of the solder ball, so that the solder is not easily re-welded to the substrate side.

Thereafter, as shown in FIG. 3, when the BGA package component 2 is pulled up by the suction jig 5 of the rework device while being sucked, the BGA package 2 is left with the terminals (bumps) 2-1 remaining on the BGA package component 2 side. The package component 2 can be removed from the mother board 1.

FIG. 4 shows another embodiment of the present invention. FIG.
In FIGS. 2 and 3, the toothpick-shaped tool 3 is attached to the mother board 1.
Although it is shown that the tool is moved on the upper side, as shown in FIG. Whether the tool 3 is provided above or below may be selected as long as it does not hinder the work in view of the arrangement of each part of the entire reworking apparatus.

In FIG. 1, FIG. 2 and FIG. 3, the string 3-1 of the toothpick type tool 3 is shown to move in a state parallel to the arrangement of the terminals (bumps) 2-1. If there is room in the width of the mold tool 3, it is better to move the string 3-1 at an angle to the arrangement of the terminals (bumps) 2-1. Less, and string 3
This is advantageous in that the solder is cut at each portion along the length direction of -1, and the load on the string 3-1 is reduced.

In FIGS. 2 and 3, the heating device 4 is shown as a hot-air heating type heating device, but the heating method is not limited to this. It is needless to say that any heating device that can maintain the temperature can be used.

The string 3-1 of the needle-shaped tool 3 is made of a metal wire to which solder does not adhere, for example, a wire formed of a metal such as stainless steel (SUS).

In the above description, the case where the present invention is applied to an LSI component having a BGA package has been described. However, it goes without saying that the present invention is effective for all semiconductor components having solder terminals (bumps). Nor.

As described above, according to the present invention, in a reworking apparatus for removing a CSP package component having solder terminals (bumps) from a substrate and reusing the same, the solder is heated between the substrate and the solder terminals (bumps). The string portion of the tool was inserted and the solder was cut on the board side. Therefore, a sufficient amount of solder remains on the terminal side of the CSP package component instead of the mother board side,
The problem that the reworked CSP package component cannot be reused due to defective bumps can be avoided.

[0033]

As described above, the present invention comprises a heating means and a component holding means. The board on which the components are mounted is heated by the heating means to melt the solder, and is mounted on the board by the component holding means. In a reworking apparatus for holding and removing a component from a substrate, a solder connection surface separating means having a thread-like cut portion is provided, and after the solder is melted, the substrate side of the molten solder at the joint surface between the substrate and the component is cut into a thread-like shape. It was cut at the part. As a result, a sufficient amount of solder can be left on the terminal side of the package component, and a component such as a CSP package with solder bumps can be reused after rework. Therefore, the number of parts required for repair can be reduced. Moreover, since the solder connection surface can be separated with a relatively simple configuration, the cost required for rework can be reduced and the work can be performed economically.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a basic operation of a rework apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a rework operation of the rework apparatus according to the embodiment shown in FIG. 1;

FIG. 3 is an explanatory diagram of a rework operation of the rework device according to the embodiment shown in FIG. 1;

FIG. 4 is an explanatory diagram of a rework operation of a rework device according to another embodiment of the present invention.

FIG. 5 is an explanatory diagram of a rework operation of a conventional rework device.

FIG. 6 is an explanatory diagram of a rework operation of a conventional rework device.

FIG. 7 is an explanatory diagram showing a cross-sectional shape of a BGA which is a CSP package component.

FIG. 8 is a schematic diagram showing an example of terminal (bump) arrangement on the back surface of the BGA shown in FIG. 7;

FIG. 9 is an explanatory view showing a sectional structure of a solder terminal (bump).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Mother board, 2, 12 ... BGA package parts, 2-1, 25 ... Terminals (bumps), 3 ... Goose-shaped tool, 3-1 ... String of goose-shaped tool 3, 4 ,
14 ... Heating device of rework device, 5, 15 ... Suction jig of rework device, 11 ... Mother board, 21 ... IC
Chip, 22 solder mask, 23 epoxy board, 24 through-hole pier, 26 copper wiring, 2
7 ... wiring wire, 28 ... molding material, 31 ... solder, 32 ... barrier metal, 33 ... silicon oxide insulating film, 34 ... aluminum pad, 35 ... silicon layer.

Claims (4)

[Claims] 1. A heating device comprising: a heating means; and a component holding means,
In a rework apparatus for heating a substrate on which components are mounted by the heating means to melt the solder and holding the components mounted on the substrate by the component holding means and removing the components from the substrate, a solder having a thread-like cut portion Reworking means comprising a connection surface separation means, wherein the solder connection surface separation means cuts the board side of the molten solder at the bonding surface between the board and the component at the thread-shaped cutting portion after the solder is melted. apparatus. 2. The thread-shaped cut portion of the solder connection surface separating means is made of a metal wire.
The rework apparatus according to item 1. 3. The rework apparatus according to claim 2, wherein the metal wire is a stainless steel wire. 4. The rework apparatus according to claim 1, wherein said heating means heats and keeps the mounting surface of said component on said substrate within a predetermined temperature range.