JPH0982716A - Manufacture of work with bump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method to easily form bumps at low cost, and to form a work with bumps which can form small bumps. SOLUTION: Paste 3 such as cream solder or organic metal compound is thinly applied on the top surface of a work 2. A laser beam radiated from a laser irradiator is reflected by a polygon mirror 7 to irradiate the paste 3 just like a spot on an electrode 10 of the work 2. Then, solidification or the like occurs in the form of a spot by the energy of the laser beam and a bump 3a is formed. Thereafter, the work incorporated with the bumps can be completed by cleaning the unset paste 3 with solvent, which was applied to a portion other than the electrode 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a work with bumps in which bumps are formed on electrodes of the work.

[0002]

2. Description of the Related Art As a method for forming bumps (protruding electrodes) on electrodes of chips or substrates cut out from a wafer to manufacture a work with bumps, a method using conductive balls such as solder balls is known. ing. This method
In this method, a conductive ball is mounted on an electrode of a work such as a chip or a substrate, and then the work is sent to a heating furnace to be heated to melt and solidify the conductive ball on the electrode to form a bump. Also known is a method of forming bumps on electrodes of a work by plating or vapor deposition means.

[0003]

However, the method using the conductive balls has a problem that it is difficult to form minute bumps, and therefore it is difficult to cope with the miniaturization and high integration of the work. In addition, the plating and vapor deposition means have a problem that it takes too much time to form bumps and the cost increases.

Therefore, it is an object of the present invention to provide a method of manufacturing a work with bumps which can form bumps easily and at low cost and can form minute bumps.

[0005]

To this end, the present invention provides a step of applying a paste, which is a material for bumps, on the surface of a work on which electrodes are formed, and irradiating the paste on the electrodes with laser light in spots. To form bumps, and a step of cleaning and removing the paste applied to the portion other than the electrodes, the manufacturing method of the work with bumps is constituted.

[0006]

According to the above construction, the bump can be formed on the electrode by irradiating the laser beam. In this case, since the laser beam can extremely narrow the luminous flux and has extremely large thermal energy, minute bumps can be formed by solidifying the paste on the electrodes in a spot manner.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a perspective view of a bump forming apparatus according to an embodiment of the present invention, and FIG. 2 is a manufacturing process diagram of the work with bumps. In FIG. 1, a work 2 is placed on a base 1. The paste 3 is thinly applied to the surface of the work 2 by screen printing means or the like. A nut 4 is connected to a side portion of the base 1. A feed screw 5 is screwed onto the nut 4. When the motor 6 is driven and the feed screw 5 rotates, the base 1 moves in the X direction along the feed screw 5.

A polygon mirror 7 is arranged above the base 1. Reference numeral 8 is a motor for rotating the polygon mirror 7. When laser light is emitted from the laser irradiator 9 while rotating the polygon mirror 7, the laser light is scanned in the Y direction and is applied to the paste 3. The paste 3 is, for example, cream solder or an organic metal compound.
When the cream solder is irradiated with laser light, it melts due to its thermal energy and then solidifies to form bumps.
Also, the organometallic compound decomposes when irradiated with laser light to deposit metal and form bumps. Examples of the organometallic compound include tetraethyl lead and tetraethyl tin.

Next, a method of forming bumps will be described with reference to FIG. In FIG. 2A, the laser light emitted from the laser irradiator 9 is reflected by the polygon mirror 7 and spotted on the paste 3 on the electrode 10 on the upper surface of the work 2. Then, the spot-shaped bumps 3a are formed by the thermal energy (FIG. 2B). In this case, the motor 6 is driven to move the work 2 in the X direction, and the polygon mirror 7 is rotated to scan the laser light in the Y direction, thereby forming a large number of matrixes formed on the upper surface of the work 2. The laser light is spotwise irradiated toward the individual electrodes 10 to form bumps 3 a on the electrodes 10.

After the bumps 3a have been formed on the electrodes 10 of the work 2 as described above, the work 2 is removed from the base 1 and the work 2 is washed with a solvent so that the parts other than the electrodes 10 are coated. The work 2 with bumps is completed by removing the uncured paste 3 (see FIG. 2).
(C)).

[0011]

According to the present invention, bumps can be easily formed on the electrodes of a work. In this case, since the laser beam can focus the light flux extremely finely and the thermal energy is extremely large, minute bumps can be formed on the electrodes, and it is possible to easily cope with the miniaturization and high integration of the work.

[Brief description of drawings]

FIG. 1 is a perspective view of a bump forming apparatus according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram of a work with bumps according to an embodiment of the present invention.

[Explanation of symbols]

 2 Work 3 Paste 7 Polygon mirror 9 Laser irradiator 10 Electrode

Claims (1)

[Claims] 1. A step of applying a paste as a material of a bump to a surface of a work on which an electrode is formed, a step of irradiating the paste on the electrode with a laser beam in a spot manner to form a bump, and a step other than the electrode And a step of cleaning and removing the paste applied to the portion of FIG.