TWI525921B - Electrical connector and method of manufacturing same - Google Patents

Description

Electrical connector and method of manufacturing same

The present invention relates to an electrical connector, and more particularly to an electrical connector for electrically connecting a wafer module and a substrate, and a method of manufacturing the electrical connector.

A common BGA (Ball Grid Array) type electrical connector is electrically connected to a printed circuit board through a solder ball disposed on a bottom surface thereof. The typical ball placement method is to solder the solder ball to the tail of the terminal. The other way is to mechanically fix the solder ball through the interference fit of the terminal or the body and the solder ball without a soldering process. For example, an electrical connector disclosed in the Chinese Utility Model Patent Publication No. 2718822 includes an insulative housing and a plurality of terminals, the insulative housing is provided with a plurality of terminal slots, and two terminals are assembled in each channel, a solder ball It is fixed to the electrical connector by being clamped by the tail portions of the two terminals.

However, when the solder ball by the interference fit is soldered to the circuit board, the oxide layer formed on the surface of the terminal may affect the bonding between the solder and the solder after the solder ball is melted, so that the solder cannot sufficiently cover the tail of the terminal, thereby causing the circuit. The electrical connection between the board and the electrical connector is not reliable.

Regarding anti-oxidation, the industry's usual practice is to apply gold material to the soldering area at the end of the terminal when manufacturing the terminal. Gold has high stability, can resist corrosion, slow oxidation, and has low electrical resistance, and can obtain good electrical conductivity. . And under the influence of the rising price of gold materials and the pressure of product cost control, the development of metal strips Continuously selective spot plating and wire plating. However, gold plating at the end of the terminal sometimes does not completely solve the problem of generating an oxide layer.

The Chinese Utility Model Patent Publication No. 2842814 discloses another electrical connector including an insulative housing and a plurality of terminals, and the insulative housing is provided with a plurality of receiving holes for receiving the terminals. This patent discloses a technique for using flux between a solder ball and a terminal solder tail, as shown in Figures 2 through 5. However, this patent does not disclose in detail how the flux is applied. From the geometry of the terminals, it is reasonable to believe that the flux is applied to the terminals after the terminal sets are loaded into the body. However, there are many inconveniences in that the terminal is assembled to the insulative housing receiving hole of the electrical connector and then the flux is applied to the solder tail. Since the terminal solder tail of the electrical connector is located almost entirely within the receiving hole, it can be difficult to apply flux to the solder tail. In addition, the flux is viscous and the excess flux on the terminal solder tails may contaminate the insulative body during handling and transportation.

In view of this, it is indeed necessary to improve the conventional electrical connectors to overcome the aforementioned drawbacks of the prior art.

It is an object of the present invention to provide an electrical connector in which a good soldering effect can be obtained between the conductive terminals and the solder to avoid void welding.

The object of the present invention is achieved by the following technical solutions: an electrical connector for electrically connecting a substrate and a chip module, the electrical connector comprising: an insulating body, a plurality of conductive terminals received in the insulating body, and a conductive terminal Contacting the plurality of solder balls, the conductive terminals are provided with a soldering portion in contact with the solder balls, the soldering portion is coated with a liquid flux, and the liquid flux is dried to leave a soldering layer on the soldering portion, the drying aid The solder layer is cleaned at a high temperature to remove the oxide layer on the surface of the solder joint, so that the molten solder ball and the solder joint A stable connection.

Compared with the prior art, the present invention has the following advantages: the flux on the conductive terminal enables the molten solder to smoothly climb the tin, better combines with the soldering portion of the conductive terminal, and the flux is dry to avoid contamination of the solder. Ontology.

10, 10'‧‧‧Insulated body

11‧‧‧ receiving holes

12‧‧‧ bottom edge

13‧‧‧ top surface

14‧‧‧Bumps

12’‧‧‧Bumps

40, 40’ ‧ ‧ main body

41, 41’‧‧‧ Connections

2, 2'‧‧‧ conductive terminals

21, 20’ ‧ ‧ base

22‧‧‧Intermediate

23‧‧‧Matement Department

24, 24'‧‧‧Docking Department

20‧‧‧ Fixed Department

25‧‧‧Weld Department

26‧‧‧ curved end

27‧‧‧Waves

271‧‧‧ summit

272‧‧‧ inclined section

273‧‧‧Arc Department

23’‧‧‧Flexible arm

25’‧‧‧Installation Department

3‧‧‧ solder balls

6‧‧‧welding layer

7‧‧‧Substrate

1 is a plan view showing a conductive terminal of an electrical connector in a first embodiment of the present invention on a tape; the second drawing is a partial cross-sectional view of the electrical connector in the first embodiment of the present invention; and the third drawing shows the present invention. A side view of a conductive terminal of the electrical connector of the first embodiment mated with a solder ball; and a fourth view is a plan view of the conductive terminal of the electrical connector of the second embodiment of the present invention on the tape; A partial cross-sectional view of an electrical connector in a second embodiment of the present invention.

The first to third figures disclose the conductive terminal 2 in the first embodiment of the present invention. The terminal strip formed by stamping of a metal material includes a strip-shaped main body portion 40 and a plurality of conductive terminals 2 connected to the main body portion 40. The main body portion 40 is formed with a plurality of connecting portions 41 on one side, and the conductive terminals 2 respectively extend downward from the connecting portion 41. Each of the conductive terminals 2 includes a base portion 21, an intermediate portion 22 extending from the base portion 21, and a mating portion 23 extending from the intermediate portion 22. The mating portion 23 is further provided with an abutting portion 24 to be in contact with a conductive sheet (not shown) of a wafer module (not shown). The amount of extension of the engaging portion 23 from the intermediate portion 22 can provide sufficient elastic force when it comes into contact with a conductive sheet (not shown) of a wafer module (not shown), and the base portion 21 is further provided with a fixing portion 20. The conductive terminal 2 further includes a downward extension from the base portion 21 The welded portion 25 is extended. The intermediate portion 22 and the engaging portion 23 may be collectively referred to as a resilient arm.

The second figure shows a partial structure of an electrical connector using the conductive terminal 2, which is mounted on a substrate 7, which includes an insulative housing 10 defining a plurality of receiving apertures 11 (only one of which is shown). The insulative housing 10 is provided with a bottom surface facing the substrate 7. The conductive terminal 2 is assembled in the receiving hole 11 of the electrical connector, and the soldering portion 25 extends from the bottom surface of the insulating body 10 to interface with a conductive element (not shown) on the substrate 7.

One of the conductive terminals 2 is assembled in each of the receiving holes 11. In the present embodiment, the receiving hole 11 is provided with a circular bottom edge 12. The solder ball 3 is fixed between the bottom edge 12 of the receiving hole 11 and the welded portion 25. The insulative housing 10 further includes a top surface 13 and a pair of bumps 14 extending upward from the top surface 13 on the side of each of the receiving holes 11 when the mating portion 23 of the conductive terminal 2 is subjected to an excessive workload. The bump 14 can protect the conductive terminal 2 and prevent the mating portion 23 from being damaged.

Referring to the third figure, the welded portion 25 of the conductive terminal 2 includes a wavy portion 27 including a peak 271, an inclined portion 272 located above the peak 271, and an arcuate portion 273 located below the peak 271. The weld portion 25 further includes a curved end 26 that extends from the curved portion 273. The peak 271 protrudes toward the solder ball 3, and the curved portion 273 and the curved end 26 surround the circumferential side of the solder ball 3. By this arrangement, the contact area between the welded portion 25 and the solder ball 3 is increased, which facilitates the subsequent surface mounting process for soldering the electrical connector to the substrate 7.

In the present embodiment, the bottom edge 12 of the receiving hole 11, the curved portion 273 of the conductive terminal 2, and the curved end 26 properly position the solder ball 3. In fact, the curved portion 273 of the bottom edge 12 and the undulations 27 provides support or restriction in the horizontal direction, while the curved end 26 provides support or restriction in the vertical direction. The solder ball 3 is then positioned at the bottom edge 12 and the curved end Between 26

Referring to the third figure, before the conductive terminals 2 are formed into the receiving holes 11 of the insulative housing 10 after being formed by stamping, the curved portion 273 of the soldering portion 25 and the curved end portion 26 are coated with oxidation resistance to facilitate soldering. Liquid flux. The solvent of the flux is isopropyl alcohol, and after volatilization, drying and shrinking, a dry soldering layer 6 which is resistant to oxidation and favors welding is formed on the surface of the welded portion 25. In practice, the flux is applied to the soldering portion 25 of the conductive terminal 2 still on the tape by a similar plating method; and then the dried conductive terminal 2 is inserted into the insulating body 10. Since the conductive terminal 2 is assembled after the flux is applied first, the flux is coated at a relatively free position and can be applied to all areas that may be combined with the solder ball 3 in order to ensure that there is sufficient area on the soldering portion 25 to assist. The solder layer improves the soldering effect of the solder portion 25 and the solder ball 3. As shown in the third figure, the curved portion 273 of the assembled conductive terminal 2 is covered by the soldering layer 6 in a wide range. One portion is located inside the insulative housing 10 and a portion is located outside the insulative housing 10. Although the third figure only shows that the curved portion 273 of the welded portion 25 and the side of the curved end 26 facing the solder ball 3 are coated with a flux, in fact, in order to obtain a better effect, it may be around the welded portion 25. The flux is applied so that the solder after the solder ball 3 is melted is better coated around the solder portion 25. Since the conductive terminal 2 is assembled after the flux is applied first, it is advantageous for the process operation, improves the production efficiency, and avoids the contamination of the insulating body 10 by applying the flux after assembling the insulating body 10.

The solder layer 6 can clean and remove the oxide layer on the surface of the solder portion 25 at a high temperature. Therefore, when the solder ball 3 is soldered by the reflow furnace, the solder layer 6 acts to remove the oxide layer existing on the surface of the soldering portion 25 due to the high temperature, and then the molten solder ball 3 can smoothly climb the tin to uniformly wrap the solder. A stable solder joint is formed around the portion 25 to prevent the molten solder ball 3 from being well bonded to the solder portion 25 due to the presence of the oxide layer. Excessive flow in the direction of the substrate 7 causes void welding.

The manufacturing method of the electrical connector comprises the following steps: (1) providing a copper material strip, stamping on the strip to form at least one conductive terminal 2, each conductive terminal 2 being provided with at least one soldering portion 25, and at the conductive terminal 2 is sequentially plated with a nickel plating layer and a gold plating layer; (2) a soldering flux is applied to the soldering portion 25 of the conductive terminal 2; (3) the conductive terminal 2 is dried to make the liquid flux on the surface of the soldering portion 25 Forming the soldering layer 6; (4) providing an insulative housing 10, the conductive terminals 2 provided with the soldering layer 6 described above are assembled into the insulative housing 10; (5) mechanically fixing the plurality of solder balls 3 to the conductive terminals (2) The flux is dropped on the solder ball 3 between the solder portion 25 of the 2 and the insulative housing 10.

The flux solvent used in the present invention is isopropyl alcohol, and the weight percentage thereof in the flux is 90% or more, and other components and corresponding weight percentages are: less than 5% of the resin, less than 5% of the surfactant, less than 3% anti-corrosion agent, and less than 1% dispersant. Among them, the resin can be selected from the following materials: Gum rosin, Wood rosin, Ester of hydrogenated rosin, Dehydrogenated rosin, and Polymerized rosin. ). The surfactant can be selected from the group consisting of Cetyltrimethylammonium bromide, Nonylphenoxypolyethoxyethanol, and Perfluoroalkyl Ethoxylate. The anti-corrosion agent can be selected from the group consisting of 2,6-Di-tert-butyl-4-methylphenol purum (BHT), triphenyl phosphite, Double-hydroquinone, 1,2,3-hydroxybenzene (1,2,3-hydroxybenzotriazole), 2-Ethylhexyl glycidyl ether, and palmitate. The dispersant can be selected from the group consisting of Nitroethane, Tetrahydrofurfuryl alcohol, Dipropylene Glycol Methyl Ether, and Diethylene Glycol Monobuthyl Ether. ) and polyethylene glycol (Polyglycol). The solvent may be ethylene glycol dimethyl ether in addition to isopropanol.

The fourth and fifth figures disclose the conductive terminal 2' in the second embodiment of the present invention, and the fourth figure discloses a tape with a plurality of said conductive terminals 2', the tape comprising a body portion 40', The main body portion 40' is provided with a plurality of connecting portions 41' connected to the conductive terminals 2. The conductive terminal 2' includes a base portion 20', a resilient arm 23' extending from the base portion 20', and a mounting portion 25' extending downward from the base portion 20'. The elastic arm 23' is provided with an abutting portion 24' that abuts against a wafer module (not shown).

The fifth figure discloses a partial structure of another electrical connector using the conductive terminal 2'. The electrical connector includes an insulative housing 10' for receiving the conductive terminal 2'. The bottom surface of the insulative housing 10' forms a plurality of protrusions 12'. The projection 12' and the mounting portion 25' of the conductive terminal 2' surround and hold and hold the solder ball 3.

Similar to the conductive terminal 2 in the first embodiment, when the conductive terminal 2' is still connected to the connecting portion 41' before being assembled to the insulating body 10', the above-mentioned mounting portion 25' is coated with the above-mentioned anti-oxidation and is favorable for soldering. The flux forms a solder layer (not shown). Therefore, when the welding is performed, the soldering layer 6 acts to remove the oxide layer existing on the surface of the mounting portion 25' due to the high temperature. Then, the molten solder ball 3 can smoothly climb the tin to uniformly wrap the mounting portion 25'. Around the surface, a stable solder joint is formed to prevent the molten solder ball 3 from being well bonded to the mounting portion 25' due to the presence of the oxide layer.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above-mentioned embodiments are merely preferred embodiments of the present invention, and the scope of the present invention is not limited to the above-described embodiments, and equivalent modifications or variations made by those skilled in the art in light of the spirit of the present invention should be It is covered by the following patent application.

20‧‧‧ Fixed Department

21‧‧‧ base

22‧‧‧Intermediate

23‧‧‧Matement Department

25‧‧‧Weld Department

26‧‧‧ curved end

27‧‧‧Waves

271‧‧‧ summit

272‧‧‧ inclined section

273‧‧‧Arc Department

12‧‧‧ bottom edge

3‧‧‧ solder balls

6‧‧‧welding layer

7‧‧‧Substrate

Claims (8)

An electrical connector for electrically connecting a substrate and a chip module, the electrical connector comprising: an insulating body; a plurality of solder balls; a plurality of conductive terminals are received in the insulating body, and the conductive terminals are provided in contact with the solder balls a soldering portion, the insulating body is provided with a bottom surface, the soldering portion extends out of the bottom surface and mechanically clamps and fixes the solder ball together with the insulating body, the soldering portion is coated with a liquid flux, and the liquid flux is dried After leaving the soldering layer on the soldering portion; during the reflow soldering, the dry soldering layer cleans and removes the oxide layer on the surface of the soldering portion at a high temperature, so that the molten solder ball smoothly climbs and wraps the soldering portion to form a stable Welding connection. The electrical connector of claim 1, wherein the flux component comprises: an isopropyl alcohol solvent having a content of >90% or an ethylene glycol dimethyl ether solvent having a content of >90%, and a content of <5%. The resin, the content of <5% of the surfactant, the content of <3% of the corrosion inhibitor, and the content of <1% of the dispersant. The electrical connector of claim 1, wherein the soldering portion of the conductive terminal is a wavy portion having a peak formed from a vertical direction, and the wavy portion is provided with a surrounding ball under the peak. The curved portion is further provided with an inclined portion above the peak, and the wave portion can control the soldering height of the solder ball to be melted does not exceed the peak. The electrical connector of claim 1, wherein the conductive terminal is inserted into the insulative body after the flux is applied, and the portion of the solder portion covered by the solder layer is partially located in the insulating body. The insulating body is partially extended to ensure that the soldering layer is provided in a sufficient area on the soldering portion. The electrical connector of claim 4, wherein the flux is applied to the soldering portion Around, so that the tin material after the solder ball is melted surrounds the welded portion. A manufacturing method of an electrical connector, wherein the electrical connector comprises an insulating body, a plurality of conductive terminals fixed in the insulating body, and a plurality of solder balls in contact with the conductive terminals, and the manufacturing method of the electrical connector comprises the following steps: (1) providing a strip of copper material, stamping at least one of the conductive terminals on the strip, each of the conductive terminals having at least one soldering portion, and plating a nickel plating layer on the conductive terminal; (2) a soldering flux is applied to the soldering portion of the conductive terminal; (3) drying the conductive terminal to form a soldering layer on the surface of the soldering portion; (4) providing an insulating body, the insulating The main body is provided with a bottom surface; (5) the conductive terminal is assembled into the insulating body, the soldering portion is extended out of the bottom surface, and the solder ball is clamped and fixed together with the insulating body; (6) the electrical connector is performed In the re-weld welding, the soldering layer acts to remove the oxide layer existing on the surface of the soldering portion due to the high temperature, and then the molten solder ball can smoothly climb the tin to uniformly wrap the periphery of the soldering portion to form a stable Point. The method of manufacturing the electrical connector of claim 6, wherein the flux comprises a component and a corresponding weight percentage: more than 90% of an isopropanol solvent or a content of >90% of ethylene glycol Ether solvent, less than 5% resin, less than 5% surfactant, less than 3% corrosion inhibitor, and less than 1% dispersant. The method of manufacturing the electrical connector of claim 6, wherein the conductive terminal is inserted into the insulative body after the flux is applied, and the portion of the solder portion covered by the solder layer is partially insulated. In the body, the insulating body is partially extended to ensure that the soldering layer is provided in a sufficient area on the soldering portion.