JPH0637121A - Method and device for removing foreign matter - Google Patents

Abstract

PURPOSE:To improve the foreign matter removing effect of the title method and device so as to improve the yield and reliability of a semiconductor package, etc., by alternately repeating a process for blowing air upon the prescribed area of an object to be processed and another process for sucking air from the prescribed area. CONSTITUTION:Foreign matters existing in a prescribed area of an object 5 to be processed are removed by alternately repeating a process for blowing air upon the prescribed area of the object and another process for sucking air from the prescribed area. In addition, the title device 1 is provided with an air blowing nozzle 11a through which the air is blown upon the prescribed area of the object 5, air sucking nozzle 11b through which the foreign matters are removed by sucking the air from the prescribed area of the object 5, and air switching control section 17 which controls the switching of air blowing and air sucking so that the air blowing and air sucking can be performed alternately. For example, the object 5 is a semiconductor package and the nozzles 11a and 11b are integrally formed in a coaxial state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for removing foreign matter, and more particularly to a technology effectively applied to a method and apparatus for removing foreign matter generated in a semiconductor package manufacturing process.

[0002]

2. Description of the Related Art For example, a method using an air jet nozzle is known as a method for removing foreign matter generated in the process of assembling a semiconductor package.

According to this method, air having a constant pressure ejected from an air injection nozzle provided in the foreign substance removing chamber is continuously blown to the semiconductor package housed in the foreign substance removing chamber, so that the floating foreign substance is removed. In the foreign matter removing chamber, the foreign matter is removed to the outside through a suction duct provided separately from the air injection nozzle.

However, in the case of this conventional technique, only the air having a constant pressure from the air injection nozzle is blown onto the semiconductor package, and the suction duct is used exclusively for sucking the foreign matter floating in the foreign matter removing chamber.

Regarding the necessity and detection method for screening foreign matter generated in the process of assembling a semiconductor package, for example, Applied Technology Publishing Co., Ltd., 1988 11
It is described in "Mounting Technology of Surface Mount Type LSI Package and Improvement of Its Reliability", P287 to P288, issued on March 16th.

[0006]

However, the inventor of the present invention has found that the above-mentioned conventional foreign matter removing method has the following problems.

That is, conventionally, only air having a constant pressure is blown to the semiconductor package, so that, for example, foreign matter is electrostatically attached to the semiconductor package,
If it enters into a corner or a recess, the foreign matter may not be blown up, and there is a problem that the foreign matter cannot be removed sufficiently.

The present invention has been made in view of the above problems, and an object thereof is to provide a technique capable of improving the foreign substance removing effect.

Another object of the present invention is to provide a technique capable of improving the yield and reliability of semiconductor packages.

The above and other objects and novel features of the present invention will be apparent from the description of the specification and the accompanying drawings.

[0011]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, according to the first aspect of the present invention, the step of injecting air to a predetermined area of the object to be processed and the step of sucking air in the predetermined area are alternately repeated to predetermined the object to be processed. The foreign matter existing in the area is removed.

[0013]

According to the first aspect of the present invention, not only the air is jetted, but also the air in the jetting area is sucked and the foreign matters existing in the area are sucked to remove the foreign matters which do not float by the air jetting. Can also be removed.

Further, by alternately repeating the air injection and the air suction, a large pressure gradient can be generated in the area where the air is jetted and sucked, and the foreign matter acts in opposite directions. Forces can be applied alternately.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a foreign matter removing apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of a main part of an object to be processed, and FIG. 3 is an enlarged sectional view of an air nozzle of the foreign matter removing apparatus of FIG. 4 is a graph showing a timing example in which air injection and air suction are alternately repeated within a predetermined time for a predetermined region of the object to be processed, FIG.
6 is a sectional view of a main part of the object to be processed before the foreign matter removing process, FIG.
And FIG. 7 is a cross-sectional view of a main part of the object to be processed during the foreign matter removing process.

The foreign matter removing apparatus of this embodiment will be described below with reference to FIGS. The foreign matter removing apparatus 1 of this embodiment shown in FIG. 1 is an apparatus for removing foreign matter generated during, for example, an assembly process of a semiconductor package.

The foreign matter removing apparatus 1 comprises a loader chamber 2, a foreign matter removing chamber 3 and an unloader chamber 4. Loader room 2
The semiconductor package (object to be processed) 5 after the wire bonding process, for example, is housed in. The loader chamber 2 has a structure capable of housing a plurality of semiconductor packages 5. The semiconductor package 5 is shown in FIG.

A semiconductor chip 7 is bonded onto a base substrate 6 of the semiconductor package 5 with its main surface facing upward. The semiconductor chip 7 is made of, for example, silicon (Si) single crystal, and a semiconductor integrated circuit such as a logic circuit or a memory circuit is formed on its main surface.

On the other hand, on the base substrate 6, the leads 8 are joined to the periphery of the semiconductor chip 7 via a joining portion 9 made of, for example, low melting point glass. Lead 8
Are electrically connected to the semiconductor integrated circuit on the main surface of the semiconductor chip 7 via the bonding wires 10. The bonding wire 10 is made of gold (Au), for example, and its diameter is, for example, about 50 μm.

In the foreign matter removing chamber 3 of the foreign matter removing apparatus 1, an air nozzle 11 and a suction duct 12 are installed.

The air nozzle 11 is installed in such a state that it can be operated vertically and obliquely with respect to the main surface of the semiconductor package 5. As shown in FIGS. 1 and 3, the air nozzle 11 of the present embodiment includes a hollow circular tube-shaped air injection nozzle 11a and a hollow circular tube-shaped air suction nozzle 11b that surrounds the air injection nozzle 11a with the same axis. It consists of

As shown in FIG. 1, the air injection nozzle 11a is mechanically connected to the pressurized air injection unit 15 via an air filter 13a and an air control valve (air switching control unit) 14a. On the other hand, the air suction nozzle 11b includes an air filter 13b and an air control valve (air switching control unit) 1
It is mechanically connected to the vacuum pump 16a via 4b.

The air filters 13a and 13b are filters for trapping foreign matter. Air control valves 14a, 14
b is electrically connected to the control unit (air switching control unit) 17, and has a structure for opening and closing each valve (not shown) based on a control signal from the control unit 17.

In this embodiment, the air control valve 14a,
Each of the valves 14b is controlled to open and close alternately, and as a result, as shown in FIG. 4, air from the air nozzle 11 to a predetermined area is maintained for a predetermined time, for example, several seconds to several tens of seconds. The injection (pressurization) and the suction of air from the predetermined area to the air nozzle 11 are alternately repeated at substantially the same time.

At this time, the foreign matter sucked by the air suction process is removed through the air suction nozzle 11b. Further, the foreign matter floating in the foreign matter removing chamber 3 by the air injection process is removed through the suction duct 12. The suction duct 12 is mechanically connected to the vacuum pump 16b, and the air in the foreign matter removal chamber 3 is constantly sucked by the vacuum pump 16b.

The unloader chamber 4 is adapted to accommodate the semiconductor package 5 which has been subjected to the foreign matter removing process. The unloader chamber 4 has a structure capable of accommodating a plurality of semiconductor packages 5.

Doors 18a and 18b are installed between the loader chamber 2 and the foreign matter removing chamber 3 and between the foreign matter removing chamber 3 and the unloader chamber 4, respectively, so that the doors 18a and 18b can be automatically opened and closed. The transfer of the semiconductor package 5 from the loader chamber 2 to the foreign matter removing chamber 3 and from the foreign matter removing chamber 3 to the unloader chamber 4 is automatically performed by the belt conveyor 19.

Next, the foreign matter removing method of this embodiment will be described with reference to FIGS.

FIG. 5 shows a main part of the semiconductor package 5 before the foreign matter removing process, and foreign matter 20a to 20e are present on the semiconductor package 5. Foreign object 20a ~
20e are present at the following positions, respectively.

The foreign matter 20a exists in the corner formed by the semiconductor chip 7 and the base substrate 6. The foreign matter 20b has entered the concave portion formed on the main surface of the semiconductor chip 7. The foreign matter 20c exists in a flat area on the main surface of the semiconductor chip 7. The foreign matter 20d has entered the concave portion (cavity) of the base substrate 6. The foreign matter 20e is present on the lead 8.

First, as shown in FIG. 6, pressurized air having a constant pressure is jetted to the semiconductor package 5 from the air jet nozzle 11a for a given time.

By this processing, for example, the foreign matter 20c existing in the flat area on the main surface of the semiconductor chip 7, the foreign matter 20e on the lead 8 and the like are blown up by the pressurized air and removed through the suction duct 12 (see FIG. 1), Foreign object 20a in the corner
It is assumed that the foreign matter 20b, 20d, etc. in the concave portion remain as they are.

At this time, it is considered that the foreign matter 20b in the recess can be blown up by increasing the pressure of the pressurized air.
May bend, causing a problem such as a short circuit between the adjacent bonding wires 10. Therefore, the air pressure may not be increased.

Therefore, in this embodiment, the air injection from the air injection nozzle 11a is stopped, and this time, as shown in FIG. 7, the air in the area where the air is injected is sucked for a predetermined time by the air suction nozzle 11b. To do. As a result, the foreign matter 20a in the corner and the foreign matter 20b, 20d in the recess are removed through the air suction nozzle 11b.

In the present embodiment, a large pressure gradient is generated in the region where the air is jetted and sucked by alternately repeating the injection of the pressurized air and the suction of the air within a predetermined time. In addition, it is possible to alternately apply forces acting on the foreign matter in opposite directions. As a result, it is possible to remove, for example, electrostatically adhered foreign matter or foreign matter that has entered recesses or corners.

As described above, according to this embodiment, the following effects can be obtained.

(1). A step of blowing air from the air injection nozzle 11a to a predetermined region of the semiconductor package 5,
By alternately repeating the step of sucking the air in the predetermined region with the air suction nozzle 11b to remove the foreign matter, it is possible to remove the foreign matter that does not float only by injecting the air.

(2). A step of blowing air from the air jet nozzle 11a to a predetermined region of the semiconductor package 5,
By alternately repeating the step of sucking the air in the predetermined area by the air suction nozzle 11b and removing the foreign matter, a large pressure gradient can be generated in the area where the air is jetted and sucked, and It is possible to alternately apply forces acting in opposite directions.

(3) Due to the above (1) and (2), for example, the foreign matter that is electrostatically attached or the foreign matter 20a, 20b, 2 that has entered the corners / recesses without increasing the pressure of the pressurized air.
Even 0d or the like can be removed, and the foreign substance removing effect can be improved.

(4) Due to the above (3), the foreign matter can be removed without causing the bending defect of the bonding wire 10 due to the pressure of the pressurized air.

(5). Due to the above (3) and (4), the yield and reliability of the semiconductor package 5 can be improved.

The invention made by the inventor of the present invention has been specifically described above based on the embodiments, but the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the above-described embodiment, the case where the present invention is applied to the foreign matter removing process after the wire bonding process which is one of the assembling processes of the semiconductor package has been described, but the present invention is not limited to this and various modifications are made. This is also possible, and can be applied to, for example, a foreign matter removing process before the wire bonding process.

Further, in the above embodiment, the case where the air injection time and the suction time are set to be substantially the same has been described, but the present invention is not limited to this, and for example, the air suction time is longer than the air injection time. May be made longer, or conversely, the air injection time may be made longer than the suction time.

In the above description, the case where the invention made by the present inventor is mainly applied to the foreign matter removing technique used in the manufacturing process of the semiconductor package which is the background field of application has been described, but the invention is not limited to this. It can be applied in various ways, for example, it can be applied to other foreign matter removing methods such as a foreign matter removing method used in the manufacturing process of photomasks and liquid crystal substrates.

[0046]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

That is, according to the invention of claim 1,
Not only the air injection, but also the air in the injection area is sucked and the foreign matter existing in the area is sucked, so that the foreign matter that does not float by the air injection can be removed.

Further, by alternately repeating the air injection and the air suction, a large pressure gradient can be generated in the area where the air is jetted and sucked, and the foreign matter acts in opposite directions. Forces can be applied alternately.

As a result, it is possible to remove, for example, electrostatically adhering foreign substances and foreign substances that have entered the corners / recesses, so that the foreign substance removing effect can be improved.

Therefore, by applying the present invention to, for example, foreign matter removal in the manufacturing process of a semiconductor package, the yield and reliability of the semiconductor package can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a foreign matter removing device that is an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a main part of an object to be processed.

3 is an enlarged cross-sectional view of an air nozzle of the foreign matter removing device of FIG.

FIG. 4 is a graph showing a timing example in which air injection and air suction are alternately repeated within a predetermined time for a predetermined region of the object to be processed.

FIG. 5 is a cross-sectional view of a main part of the object to be processed before the foreign matter removing process.

FIG. 6 is a cross-sectional view of a main part of the object to be processed during the foreign matter removing process.

FIG. 7 is a cross-sectional view of the main parts of the object to be processed during the foreign matter removing process subsequent to FIG. 6;

[Explanation of symbols]

 1 foreign matter removing device 2 loader chamber 3 foreign matter removing chamber 4 unloader chamber 5 semiconductor package (object to be processed) 6 base substrate 7 semiconductor chip 8 lead 9 bonding portion 10 bonding wire 11 air nozzle 11a air injection nozzle 11b air suction nozzle 12 suction duct 13a Air filter 13b Air filter 14a Air control valve (air switching control part) 14b Air control valve (air switching control part) 15 Pressurized air injection part 16a Vacuum pump 16b Vacuum pump 17 Control part (air switching control part) 18a Door 18b Door 19 belt conveyor 20a foreign matter 20b foreign matter 20c foreign matter 20d foreign matter 20e foreign matter

Claims (5)

[Claims] 1. A foreign matter existing in a predetermined area of the object to be processed is alternately repeated by a step of injecting air to the predetermined area of the object to be processed and a step of sucking air in the predetermined area. A method for removing foreign matter characterized by the above. 2. A step of ejecting air to a predetermined area of the semiconductor package and a step of sucking air in the predetermined area are alternately repeated to remove foreign matters existing in the predetermined area of the semiconductor package. Characteristic foreign material removal method. 3. An air injection nozzle for injecting air to a predetermined area of the object to be processed, an air suction nozzle for removing foreign matter by sucking air in the predetermined area of the object to be processed, and an injection of the air. And an air switching control unit that controls switching between air injection and suction so that air suction and air suction are alternately performed. 4. An air jet nozzle for jetting air to a predetermined area of a semiconductor package, an air suction nozzle for removing foreign matter by sucking air in a predetermined area of the semiconductor package, and jetting and air of the air. A foreign matter removing device, comprising: an air switching control unit that controls switching between injection and suction of air so that the suction and the suction are alternately performed. 5. The foreign matter removing device according to claim 3, wherein the air injection nozzle and the air suction nozzle are integrally formed with the same axis.