JP3119385B2 - Surface treatment method, surface treatment device and surface treatment liquid for electronic components and their electrode terminals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method, a surface treatment apparatus, and a surface treatment liquid for an electronic component, such as an LSI chip, which is soldered and mounted on a substrate, and its electrode terminals.

[0002]

2. Description of the Related Art In order to mount an electronic component such as an LSI chip on a printed circuit board by soldering, a flux (generally, a rosin-based flux) which plays a role of cleaning and improving wettability of a metal surface to be soldered, and a solder. Is necessary. For example, as shown in FIG. 7, cream solder 8 (which is made by mixing solder particles and flux to form a cream) is printed on the terminal surface 7 of the printed circuit board, and the electrode terminals 2 of the electronic component 1 are printed thereon.
And a step of heating in a reflow furnace.

FIG. 8 shows this electronic component mounting machine. That is,
Terminal surface 7 of printed circuit board by cream solder printing machine 10
Then, the cream solder 8 is printed on the printed circuit board, the electronic component 1 is placed on the printed board by the chip mounter 11, and the cream solder 8 is heated and melted in the reflow furnace 12 to be soldered and mounted.

In this case, the electrode terminals of the electronic component are soldered or tin-plated (3 to 5 μm) in order to improve the solder wettability.
m). Since this plating is for the purpose of improving the wettability, plating is not performed with a thickness of 5 μm or more.

[0005]

However, with the recent miniaturization of electronic equipment, miniaturization of electronic components has been rapidly progressing. When electronic components are miniaturized, the electrode terminal pitch of a printed circuit board on which these electronic components are mounted also becomes fine, so that soldering to a fine pattern is required. However, as shown in FIG. 7, the soldering of the fine pattern has a problem in that the yield of the soldering process is reduced due to the occurrence of solder balls 9 and the occurrence of short-circuit between electrodes due to soldering.

SUMMARY OF THE INVENTION An object of the present invention is to prevent the generation of solder balls and short-circuiting between electrodes, thereby enabling electronic components to be mounted on a fine pitch and to reduce the cream solder printing process, and the surface of electrode terminals thereof. An object of the present invention is to provide a treatment method, a surface treatment device and a surface treatment liquid.

[0007]

A first aspect of the present invention is a method for treating a surface of an electrode terminal in an electronic component, the method comprising the steps of: dissolving a rosin flux adsorbed with a cationic surfactant in a solder or tin electrolyte; A step of immersing the electrode terminal of the electronic component in the substrate, and a step of depositing a rosin-based flux in which a cationic surfactant is adsorbed together with the solder or tin on the surface of the electrode terminal. ◇ A second invention is a surface treatment device for an electrode terminal of an electronic component, wherein the rosin-based surface treatment method for an electrode terminal of an electronic component has a cation- based surfactant adsorbed thereon. First means for immersing an electrode terminal of an electronic component in a solder or tin electrolyte in which a flux is dispersed; and a rosin flux in which a cationic surfactant is adsorbed on the surface of the electrode terminal together with the solder or tin. And second means for depositing ◇ third invention, Kachio an electronic component, and the electrode terminals of the electronic component, the electrode terminal
By immersing the emissions-based surfactant in the solder or tin electrolyte solution is dispersed rosin flux was adsorbed to adsorb the cationic surfactant deposited with the solder or tin to the surface of the electrode terminal Rosin flux. ◇ fourth invention is a surface treatment solution of the electrode terminals in the electronic component, Kachio
And a rosin flux in which the cationic surfactant is adsorbed, and a solder or tin electrolyte in which the rosin flux is dispersed. It is characterized in that a rosin flux onto which a cationic surfactant is adsorbed is deposited.

[0008]

According to the present invention, a rosin flux in which a cationic surfactant is adsorbed together with solder or tin is deposited on the surface of an electrode terminal by having the means described above, and the above electrode is mounted on a substrate when mounted on a substrate. Rosin flux that adsorbs solder or tin and cationic surfactant deposited on the surface of the terminal allows soldering without generating solder balls or shorting between electrodes, even when mounted on a fine pitch. An electronic component that can be performed can be obtained.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a perspective view showing an external configuration of the LSI chip 1. The LSI chip 1 has a plurality of electrode terminals 2. The electrode terminal 2 is formed by pressing a hoop material.

FIG. 2 is a flow chart for explaining steps from the step of forming the electrode terminals 2 of the LSI chip 1 from the hoop material as the material of the electrode terminals. The hoop material is first stamped into a shape of an electrode terminal by a pressing process to form an electrode terminal. FIG. 3 is a plan view showing the hoop material 3 after the press working. The hoop material 3 is formed with a plurality of strip-shaped portions 3a to become electrode terminals by press working. When the pressing step is completed, the hoop material 3 proceeds to a plating step.

FIG. 4 is a diagram showing details of the plating step.
The hoop material 3 after the press working is wound around the reel 4. The hoop material 3 unreeled from the reel 4 is transported to the plating device 5. In the plating apparatus 5, after passing through a pretreatment step of removing dirt such as press oil adhered to the hoop material 3,
Proceed to plating step (electrolytic plating). In the plating step, a plating solution in which flux particles are dispersed is used.

FIG. 5 is a view showing the concept of dispersing flux particles in a plating solution. Here, the rosin-based flux is obtained by dissolving rosin (containing 80 to 90% by weight of abietic acid) as a main component in a solvent such as IPA (isopropyl alcohol) at 20 to 50% by weight / volume%. The flux particles of the rosin-based flux are fine particles having a diameter of 3 μm or less. When dispersing the flux particles in the cationic surfactant, Kachio around the flux particles
The flux-type surfactant particles are adsorbed and the flux particles themselves are charged with “+”. Then, solder (an alloy of tin and lead) is dissolved in an electrolytic solution, and flux particles in which cationic surfactant particles are adsorbed are added at a ratio of 10 to 15% by weight to a plating solution containing Sn2 + and Pb2 + ions. And disperse.

Returning to FIG. 4, in the plating step, electrolytic plating is performed using the above-mentioned plating solution. That is, the hoop material 3 serving as an electrode terminal and the solder electrode (plate-like solder) are immersed in the plating solution. Next, an electric current is passed using the hoop material 3 as a “−” electrode and the solder plate as a “+” electrode. in this case,
The plating thickness is determined by the amount of current and time. In this embodiment, the plating thickness is larger than the normal plating thickness (3 to 5 μm), and solder is deposited on the surface of the hoop material 3 to a plating thickness of 10 to 20 μm. At this time, the plating solution Kachio
Since the flux particles having the adsorbed surfactant particles dispersed therein, the solder and the flux particles are both precipitated (eutectoid) on the surface of the hoop material 3.

When the plating process is completed, the process proceeds to a cleaning process, in which the hoop material 3 is cleaned, and then proceeds to a drying process to be dried. Then, the hoop material 3 that has exited the plating device 5 is taken up on a take-up reel 6.

Returning to FIG. 2, when the plating step is completed,
Next, the process proceeds to the bonding step. In this bonding step, the LSI chip is mounted on the hoop material 3 on which the solder and flux particles are plated, and the band-shaped portion 3a of the hoop material 3 that becomes the electrode terminal 2 and the LSI chip are bonded. When this bonding process is completed, the process proceeds to a molding process. In the molding step, the bonded LSI chip is molded with resin. When the molding process is completed, unnecessary portions of the hoop material 3 are cut to separate the plurality of electrode terminals 2 (band-like portions 3a) from each other, and the LSI chip 1 having the shape shown in FIG. 1 is completed.

Since the flux is deposited together with the solder on the surface of the electrode terminal 2 of the LSI chip 1 by the above-described process, unlike the cream solder, a small amount of the solder and the flux can be supplied uniformly, and the cream solder is used. No need. That is, as shown in FIG. 6, the electrode terminals 2 of the LSI chip 1 are positioned on the terminal surfaces 7 of the printed circuit board by the chip mounter 11 shown in FIG. The solder is thermally melted in this order, and the electrode terminals 2 are soldered to the terminal surfaces 3 of the printed circuit board.

[0017]

According to the present invention, a rosin flux in which a cationic surfactant is adsorbed together with solder or tin is deposited on the surface of an electrode terminal, and is deposited on the surface of the electrode terminal when mounted on a substrate. Solder or tin and katio
Emissions-based surfactant can be obtained an electronic component capable of performing soldering to the substrate by rosin flux was adsorbed, the electronic component mounting to a fine pitch by preventing the occurrence and a short circuit between electrodes of the solder balls And a surface treatment method, a surface treatment apparatus, and a surface treatment liquid for an electrode component capable of reducing the cream solder printing step, and the electrode terminal thereof.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an external configuration of an LSI chip.

FIG. 2 is a flowchart showing an operation until a hoop material is processed into an LSI electrode.

FIG. 3 is a view showing a hoop material after pressing.

FIG. 4 is a diagram showing a plating step of a hoop material.

FIG. 5 is a conceptual diagram showing a state in which flux particles are dispersed in a plating solution.

FIG. 6 is a diagram showing a mounting structure that does not use cream solder.

FIG. 7 is a diagram showing a conventional mounting state using cream solder.

FIG. 8 is a diagram showing a series of devices from a cream solder printing machine to a reflow furnace.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... LSI chip 2 ... Electrode terminal 3 ... Hoop material 4 ... Reel 5 ... Plating device 6 ... Take-up reel 7 ... Terminal surface 8 ... Cream solder 9 ... Solder ball 10 ... Cream solder printer 11 ... Chip mounter 12 ... Reflow furnace

Claims (4)

(57) [Claims] 1. A step of immersing an electrode terminal of an electronic component in a solder or tin electrolyte solution in which a rosin flux in which a cationic surfactant is adsorbed is dispersed, and the surface of the electrode terminal together with the solder or tin. Depositing a rosin flux onto which a cationic surfactant has been adsorbed. 2. A method for treating an electrode terminal of an electronic component, the method comprising: treating a surface of an electrode terminal of the electronic component with a solder or tin electrolyte in which a rosin flux to which a cationic surfactant is adsorbed is dispersed. A first means for immersing the electrode terminal of the present invention; and a second means for depositing a rosin flux in which a cationic surfactant is adsorbed together with the solder or tin on the surface of the electrode terminal. Surface treatment device for electrode terminals in electronic components. 3. An electrode terminal, and the electrode terminal is immersed in a solder or tin electrolyte in which a rosin flux in which a cationic surfactant is adsorbed is dispersed, so that the solder or tin is applied to the surface of the electrode terminal. Deposited with
An electronic component comprising: a rosin flux to which a cationic surfactant is adsorbed. 4. A coating composition comprising a cationic surfactant, a rosin flux to which the cationic surfactant is adsorbed, and a solder or tin electrolyte in which the rosin flux is dispersed. Ca with the solder or tin to the processing material surface
A surface treatment liquid characterized by depositing a rosin flux onto which a thione surfactant is adsorbed.