JPS60240142A - Solder-bump forming method - Google Patents

Abstract

PURPOSE:To form a solder bump efficiently by a small number of tools and man-hours, by directly dropping the fused solder on a substrate. CONSTITUTION:Solder 3 is contained in a fused solder container 2, which is surrounded by a heater 1. The solder 3 is fused by the heater 1, at, e.g., 200 deg.C. At the bottom side of the fused solder container 2, a nozzle 6 having a cavity 5, in which a piezoelectric element 4 is arranged, is provided. The nozzle 6 has, e.g., one opening 7. Its diameter is about 50mum-1mm.. The fused solder 3 is suitably compressed by the piezoelectric element 4 and dropped on, e.g., on a wiring substrate 8 through the opening 7 of the nozzle. Thus a solder bump 9 is formed. The wiring substrate 8 is mounted on an X-Y table, which can be automatically controlled. The movement of the X-Y table is controlled by a control device using, e.g., a microcomputer and the like. The solder bump, which has an intended size, can be formed at an intended position.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a method for forming solder bumps, and particularly to a method for forming solder bumps for electrically connecting semiconductor chips, wiring boards, etc. Background of technology In the electronics industry, ultra-miniaturization and ultra-thinness have recently become the norm, and ICs, LSIs, thick-film hybrid ICs, etc. are rapidly developing, and at the same time, advanced production capacity research for automation and labor saving is underway. is required. Therefore, workability in the manufacturing process is particularly important. The most important work in the electronics industry is the technology of joining parts by soldering, welding, pressure welding, etc. Among them, soldering is an indispensable joining technology in the electronics industry.

Prior Art and Problems Soldering is mainly done by bringing the target component into contact with the component to be welded on which a solder pad has been formed. This is done by bonding using an I-type conductor such as b-8n type.

Conventional methods for forming solder pads and knobs in which solder is adhered to solder pads (electrodes) include methods using a single solder or solder yeast, and methods for forming large quantities of solder pads, for example. There are methods that use vapor deposition or plating methods that use solder balls or solder paste. Moreover, it was inefficient because it took a long time to form the nohnder pump.

OBJECTS OF THE INVENTION In view of the above drawbacks, it is an object of the present invention to provide an easy and efficient method for forming solder bumps.

DESCRIPTION OF THE INVENTION The object of the present invention is achieved by a solder bump forming method characterized in that molten solder is appropriately dropped onto a substrate through a nozzle having at least one opening.

That is, the present invention uses a pressure element such as a piezoelectric element or a magnetostrictive element to drop a fixed amount of melted solder onto a target substrate from a nozzle with a small diameter opening to directly form solder bumps. It was designed so that it could be formed.

Examples of the invention Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a cross-sectional view for explaining one embodiment of the present invention, and FIG. 2 is a cross-sectional view for explaining another embodiment of the present invention.

In FIG. 1, solder 3 is stored in a solder reservoir 2 surrounded by a heater 1. As shown in FIG. The solder 3 is melted by the heater 1 at, for example, about 200°C. A piezo element is provided on the bottom side of the solder reservoir 2. The nozzle 6 of this embodiment has one open lower (single nozzle), and its diameter is about 50 μm to 1 m+. Melted solder 3 (appropriately pressurized by a 4-vinyl ry element 4 and dripped from the open lower part of the nozzle onto, for example, a wiring board 8 to form a solder bang 9).

The wiring board 8 is placed on an automatically controllable X-Y table (not shown), and the movement of the x-y table is controlled by a control device using, for example, a microcomputer. Form a solder bang with the desired size at the position.

The embodiment shown in FIG. 2 is a multi-nozzle system in which the number of nozzles (aperture) is increased. In this embodiment, each piezo element can be controlled independently, so that solder bangs can be formed only at necessary positions. Of course, if the formation positions of solder bumps correspond to all the openings of the multi-nozzle, many solder bumps can be formed at the same time.

As described in detail, according to the present invention, solder bumps can be formed by directly dropping molten solder onto a substrate, so solder bumps can be formed in Kumamoto style with less equipment and man-hours.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view for explaining one embodiment of the present invention, and FIG. 2 is a cross-sectional view for explaining another embodiment of the present invention. 1...Heater, 2.../Storage container, 3.../
Sunda, 4... Piezo element, 5... Capity, 6
... Nozzle, 7... Opening, 8... Wiring board, 9...
... Notaku da Panzo. Patent applicant Fujitsu Limited Patent agent Akira Aoki Patent attorney Kazuyuki Nishidate Patent attorney 1) Yukio Patent attorney Akira Yamaguchi Figure 2

Claims (1)

[Claims] 1. A method for forming solder bumps, which comprises appropriately dropping molten solder onto a substrate through a nozzle having at least one opening.