Process for soldering electric connector onto circuit board

Abstract

In a process of soldering an electric connector on a circuit board, the connector has an insulator and a plurality of leads mounted inside the insulator. Each lead has a first end extending into a soldering terminal to a bonding surface of the insulator. A soft solder paste is dispensed over a bonding surface of the circuit board. The soldering process inserts the soldering terminal of each lead in the soft solder paste and applies heat to the soft solder paste to bond the soldering terminal and the circuit board together. The direct insertion of the soldering terminal of the lead into the soft paste on the circuit board minimizes the contact area between the lead and the circuit board and prevents the solder paste from being unduly spread, causing short circuit. Furthermore, the yield and soldering reliability are increased and the production cost is reduced.

Description

[0001] 1. Field of the Invention[0002] The invention relates to a process for soldering an electric connector onto a circuit board. More particularly, the invention relates to a process of soldering an electric connector onto a circuit board with increased yield and soldering reliability and reduced production cost.[0003] 2. Description of the Related Art[0004] Bonding techniques used to attach an electric connector onto a circuit board include Direct Insertion Pin (DIP), Surface Mount Technology , and Ball Grid Array (BGA). However, these different bonding techniques may have some disadvantages.[0005] Referring to FIG. 1 and FIG. 2, an electric connector 1 and a circuit board 2 are bonded to each other by the DIP technique. A plurality of leads 3 of the electric connector 1 respectively penetrate a plurality of through holes 4 of the circuit board 2 and then a solder paste is dispensed over the through holes 4, formed by drilling the circuit board 2. The through holes 4 adversely a...

AI Technical Summary

Benefits of technology

This process increases yield and reliability by eliminating the need for drilling and reducing the risk of short circuits, while lowering production costs by ensuring consistent bonding without the need for expensive solder ball formation.

Problems solved by technology

However, these different bonding techniques may have some disadvantages.

The through holes 4 adversely affect the high integrity of circuit design, especially in the case of multi-layered routing.

One disadvantage of SMT is that when the circuit board 7 or the electric connector 5 is slightly bent or the contact portions 8 are not at the same level, some of the contact portions 8 cannot touch the solder paste 9.

When the solder paste 9 is heated, these contact portions 8 are not dipped in a flux of the solder paste 9, which causes soldering defects.

Furthermore, an oxide layer is often formed over the contact portions 8, which raises the whole resistance thereof and may even cause a soldering failure of the contact portions 8.

The above disadvantages adversely affect the performance of the electric connector 5.

As the amount of leads on the electric connector increases, it becomes more difficult to control the yield.

However, soldering the solder balls 11 on the terminals of the lead 10 needs is expensive and time-consuming.

In both SMT and BGA techniques, the respective contact areas of the solder paste and the circuit board are so large that the solder paste at the tip of each lead tends to spread out and contact with other solder paste areas, causing a short circuit.

Images