GB2310324A

GB2310324A - Ball-grid-array socket

Info

Publication number: GB2310324A
Application number: GB9603207A
Authority: GB
Inventors: Tien-Tsai Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-02-15
Filing date: 1996-02-15
Publication date: 1997-08-20
Also published as: GB9603207D0

Description

BALL - GRID -ARRAY SOCKET This invention relates to a ball-grid-array (BGA) socket and more particularly to a socket which does not require the soldering of the socket contact to the printed circuit board (PCB), which can be easily mounted or removed therefrom and which can provide a good electric contact when engaged with a PCB.

Integrated circuit chips (IC chips) are widely used in computer equipment and the conventional method of attaching an IC chip to a PCB usually involves a dip soldering process which is difficult to control as the IC chip terminal is prone to deform or bend. More advanced techniques employ surface mounting technology (SMT) for soldering the IC chip to the PCB. However SMT also has drawbacks when used with high density IC chip terminals such as BGA devices. In particularly, heat transmission to the inside surface of the terminals can be difficult and this results in poor soldering.

Inspect ion of the soldering quality cannot be performed inside grid array terminals. When there is a need to replace an IC chip because of a defect, this is not easy to do because the solder binding has to be removed. In the case of BGA packaged MPU for a computer, the device must be simply changeable to allow for computer upgrading.

In order to overcome or substantially reduce the aforementioned problems and disadvantages, this invention provides a ball-grid-array (BGA) socket that is simple to use and allows easy mounting or removal of an IC chip therefrom.

The preferred BGA socket of the present invention includes a base and a clamp. The clamp has hinge and latch openings formed in it and the base includes hinges, latches and a plastic housing. The hinge has a movable hinge hook for engaging with a hinge opening. The latch has a snap hook to engage with a latch opening and a release lever for disengaging with the latch opening.

The base has contact apertures formed in it, each of which has a contact disposed therein.

In order to use the preferred BGA socket of the invention, an IC chip is placed in the base. The clamp is then firmly secured on the base by engaging the hinge and latch with their respective openings. The contact located in the base makes firm contact with the IC chip on the top and the PCB on the bottom, resulting in an electrically conductive path being established between them.

Preferably, the base has legs disposed at the bottom to facilitate positioning on a PCB and the contact is substantially U-shaped with outwardly extending upper edges.

Lances may be formed on the two lateral sides of the contact to securely engage with the apertures in the base. Preferably, protrusive bulges are also formed under the bottom of the contact to make contact with a PCB so that a good electric connection is achieved.

The present invention overcomes or substantially reduces the soldering and high defect rate problems normally found when soldering BGA sockets. The mounting or removing of an IC chip is also made easy and simple as there is no soldering needed between the contacts and the PCB. The base is however fixed on the PCB by soldering its four corners thereto.

A preferred embodiment of the present invention will now be described, by way of example only with reference to the accompanying drawings, in which: Figure 1 is an exploded view of a BGA of the present invention; Figure 2 is a perspective view of the BGA shown in Figure 1; Figure 3A is a fragmentary section view of the BGA of Figures 1 and 2 in use; Figure 3B is a section view of a contact of the BGA of Figures 1 and 2 in use; and Figure 4 is a pictorial view, partly cutaway, of the BGA of Figures 1-3.

Referring to Figures 1-4 there is shown a BGA socket of the present invention which comprises a clamp 10 and a base 20. Hinge openings 11 and latch openings 12 are provided in the clamp 10 and the base 20 comprises a plastic housing 23, movable hinges 21 each engageable with a hinge opening 11 and movable latches 22 each engaged with a latch opening 12.

Hinge 21 has a hinge hook 211 and a release lever 222 formed thereon. The plastic housing 23 has contact apertures 24 formed therein each with a contact 25 disposed inside.

In use; a BGA chip 27 is disposed in the base 20. The clamp 10 is then placed on the base over the BGA chip 27, and hinge hook 211 engages with the hinge opening 11 and snap hook 221 engages with the latch opening 12. Thus the clamp 10 is firmly secured to the base 20.

Each contact 25 is substantially U-shaped and has outwardly extending upper edges for engaging with the leads of the IC chip 27.

A lance 251 is provided on the lateral side of the contact 25 for engaging with the apertures 24 formed in the plastic housing 23. Under the bottom of contact 25, there are provided protrusive bulges 252 to make contact with PCB 28. Thus, IC chip 27 can make a good contact with PCB 28 via contact 25 without the need of soldering.

The mounting or removal of an IC chip is simple and easy.

Pegs 26 disposed under the base 20 facilitate positioning on the PCB. Base 20 is fixed on the PCB by soldering of the four corners of the base 20 to the PCB.

It will be appreciated that the present invention provides significant improvement over conventional dip or SMT soldering methods and costs less because the time consuming soldering process is minimized. Furthermore, the mounting or removal of an IC chip is both simple and convenient.

Claims

1. A ball-grid-array socket for an integrated circuit chip comprising a clamp having hinge and latch openings therein and a base with a movable hinge having a hinge hook, a latch having a snap hook and a release lever, and a plastic housing with a plurality of apertures each with a contact disposed therein, the clamp being movably engageable with the base by engaging the hinge with the hinge opening and by engaging the latch with the latch opening, and forming an electric contact between the integrated circuit chip and a printed circuit board through the contact.

2. A ball-grid-array socket as claimed in claim 1 wherein the clamp and the base are engaged together by the movable hinge and the integrated circuit chip is disposed in the base and held by the clamp.

3. A ball-grid-array socket as claimed in claim 1 or claim 2 wherein the contact is substantially U-shaped and has upper edges which extend outwardly with a lance formed on each lateral side and a protrusive bulge formed under the bottom surface thereof.

4. A ball-grid-array socket as claimed in any preceding claim wherein pegs are disposed under the base to facilitate positioning of the base on the printed circuit board.

5. A ball-grid-array socket as claimed in claim 4 wherein the contact is substantially U-shaped and has upper edges which extended outwardly with a lance formed on each lateral side and a protrusive bulge formed under the bottom surface thereof.

6. A ball-grid-array socket for providing an electric contact between an integrated circuit chip and a printed circuit board comprising a clamp, a base and a plastic housing with a plurality of apertures therein in each of which a contact is disposed, the clamp being releasably engageable with the base and forming an electric contact between the integrated circuit chip and the printed circuit board through said contacts.

7. A ball-grid-array socket substantially as herein described with reference to the accompanying drawings.