JPS5994387A - Junction and junction product - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on British Patent Nos. 137 (1513, 1380).
No. 558 and No. 13854'73, the invention relates to novel joining means and final products newly developed in the methods described in No. 558 and No. 13854'73.

The present invention is concerned with problems that occur when making electrical connections between conductors. At least in some electrical and electronic fields, known connection methods (heat soldering, mechanical plug-and-socket connections, pressure clamping) can be damaged or unreliable. It is inconvenient because it has no gender.

In one aspect, the present invention is directed to making a permanent, strong electrically conductive connection to an electrical circuit board. The end connections or terminal pads of such substrates have been soldered into plug sockets or have been made directly mechanically by means of contact sockets of flexible conductor strips. Fluxes used in soldering or soldering can damage the board or adjacent components on the board, and mechanical methods (whether directly or through a plug socket) unreliable,
It tends to deteriorate over time.

The method does not use high pressure or high temperature conditions, allowing permanent, strong, low resistance electrical continuity to be formed without damaging the substrate or pads.

The heat generated by this method is short-lived and is as limited as possible to the interface area of the parts to be joined, so that the surrounding and adjacent areas of the parts to be joined remain substantially unaffected and the substrate will not be damaged either.

It also allows parts to be soldered onto the board, whether at the edges of the board or at other locations, without damaging the parts or the board.

The method is characterized by placing the parts to be welded in contact and pressing a rapidly rotating friction tool against an outer working surface, opposite the interface parts to be joined.

This outermost working surface may be the part to be joined or the material interposed between the high speed tool and the outermost surface of the material to be joined.

This caused the weld to occur by instantaneously generating extremely high energy levels at the contact surfaces by an ununderstood mechanism.

For similar metals, the joint region can have a homogeneous crystalline structure, whether the joint is overlapping or end-to-end.

If there are dissimilar metals within the bond area, significant alloying and diffusion will occur. However, the joints formed are mechanically strong and electrically stable with extremely low resistance.

The elbow-high energy level generated at the contact surface is
Because its strength is locally limited and short-lived, it does not heat or damage the device or substrate around or below the bonding area. It looks like

The joints do not need to be soldered, brazed or have fillers of different composites, but are made of coated materials, such as foils or sheets in the case of thermoplastic coated ones. The coating on at least one side remains virtually undamaged even after bonding.

Therefore, the actual joint itself and the product having the joint according to the invention have novel characteristics.

DESCRIPTION OF THE DRAWINGS Examples of products and welds made according to the invention, or methods of implementing the same, are shown in conjunction with the accompanying drawings.

Example 1 A ribbon cable or flexible circuit 1 (FIGS. 1 and 2) is suitably held on a printed circuit board and made of Kapton (Nemouvs for polyimide).
Each copper track 3 (Trademark of DuPont) is disposed in direct contact with a terminal pad 4 on the printed circuit board. The ribbon cable and printed circuit board are mounted on the moving table in this position.

The moving table is set to move along the trunk at a linear speed of 85 mm per second and transport the track beneath the rotating tool. This rotating body is Kapt
on contact with the surface of the insulator and 3500 Orpm
It has a steel rotary body rotating at 100 mm and passes in turn over each copper track such that its direction of movement is perpendicular to the direction of the conductor. The diameter of the rotating body is 381 m, and the contact friction surface is 1 mz.

By doing so, the Kapton insulation immediately behind each copper track is removed and a bond 5 is formed between the copper track and the corresponding copper terminal on the printed circuit board.

Neither the copper conductor tracks on the Kapton nor the terminals on the printed circuit board need to be clean, and the joints formed are mechanically strong and electrically in good contact. In addition to the materials mentioned above, the terminals may be silver-plated copper, tin-plated copper, or copper coated with various other metals, including gold. The conductor of the flexible ribbon cable may be, for example, aluminum. The Kapton or other insulation of the cable may of course be removed from the conductors prior to the splicing process.

This method eliminates the mechanical connection (a major cause of failure) to the printed circuit board's terminal pads, and the soldering process eliminates the heat and flux used in the process, which can cause damage to the board, especially when soldering. It is also recognized that obstacles occurring on flexible or multilayer substrates can be eliminated.

According to this method, even if there is a metal for brazing or soldering between the conductor to be joined and the terminal butt, or if there is a coating with such metal, the flux can be used. Not used.

If a breakable connection is required to join two circuit boards, a flexible ribbon cable or flexible circuit tail can be permanently attached to each by the method;
A single mechanically severable connection between the two flexible circuits or tails may be cut off where mechanical misconnections can occur.

Example 2 When heat is applied during soldering or during flow soldering, by a soldering iron or by placing the electronic component in an oven, the electronic component may be damaged by its own heating. be.

These parts, packages, carriers, and carrier lids. By using this method of spot or friction seam joining the connections or their surroundings, the solder can be reflowed in a limited area, such as an elbow, without applying heat to the rest of the component. Also, a strong bond or hermetic seal can be achieved with this method.

In particular, the method may be used for packaging integrated circuits. They are generally packaged hermetically to exclude moisture and other materials and have strong external leads suitable for mounting the package on a printed circuit board. The preferred structure for the external lead strands is two rows of equal number of pins, which either pass through corresponding holes in the circuit on the printed circuit board, or are inserted along the length of each pin onto corresponding terminals on the printed circuit board. It is designed to place the part in the direction. The body of the package is made of ceramic material, and the lid and external leads are made of Kovar (Fe5
4%, Ni 29%, Co 17%).

Metal lids often need to be electrically connected to the printed circuit on which the shoe cage is mounted, and this is accomplished by soldering the lid to a pre-installed metal layer on the body of the shoe cage. You can also do this by Such integrated circuit packages are often referred to as "single chip carriers".

a) Gold-coated lid glue flow of metal to gold-coated ceramic silicon chip carrier using a solder deposit layer on the chip carrier in the area where the lid is to be fixed. is fixed to the chip carrier by adhesive tape, and one side to be joined is left open. The carrier and lid are suitably mounted on a rotating table. A moderately polished hardened steel rotating body with a diameter of 42 mm and a width of 3°2 yr:m is constructed such that only one flaw on the edge of the rotating body contacts the outer edge of the chip carrier lid during the bonding operation. It is positioned in Rotary tool is 20,000 rp
It is switched on at a rotational speed of the rotating body which is preset to m. The speed of the moving table is 70m per second.
m is set. When the table is activated, the rotating body momentarily contacts the edge of the lid, the solder reflows, and the lid is joined to the carrier. Although each side of the lid is bonded to the carrier, this bonding effect is limited to the area of contact between the rotating body and the edge of the lid, and is only for a short time, so that large amounts of heat may be generated in the parts. do not have.

The difficulty of attaching very thin, closely spaced connectors to printed circuit board connector pads is well known. In one example not shown here, the connector pads and connectors are
The width is 1 mm and the spacing between them is Q, 20 r
It is ua. The component is properly installed such that the connector pads and connector are aligned and the intervening mask is applied over the component to hold the pads and connector firmly in place. The material of the mask placed between
A glass cloth or paper coated with polytetrafluoroethylene (apton or other such material) and placed between the friction rollers and the connector to hold and protect them in place. .

It has a hardened steel rotating body with a diameter of 50 mm and a working friction surface of 1
A rotary tool rotating at a speed of 15.00 Orpm makes light contact with the surface of the intermediate material as the moving table carrying the printed circuit board passes underneath. In this way, lead-containing soot)
The connector and the connection pad are reflow bonded. The intermediate material is removed after the joining operation.

Many other electronic packages and components can be reflow soldered in this manner, creating new ways to join tightly packed components and creating many new products.

[Brief explanation of the drawing]

FIG. 1 shows a circuit board to which the copper conductors of a flexible ribbon cable are bonded on both sides. FIG. 2 is a diagram showing a ribo:/cable bonded to a circuit board via a Kelphl insulator. ]... Ribbon cable, 2... Printed circuit board,
3...Copper track, 4...Terminal pad, 5...
joint.

Claims (7)

[Claims] (1) Conductive electrical components permanently connected together by bonding the components together without applying heat. (2) said joining is accomplished by passing a rapidly rotating friction rotor across the opposite surface of one part while bringing the surface of one part into contact with the surface of the other part; An electrical component according to claim 1, wherein the contact surfaces are joined by. (3) The electrical component according to claim 1, wherein the one component is a printed circuit board and the other component is a chip or a chip carrier. (4) The electrical component according to claim 1 or 2, wherein the one component is a printed circuit basic board and the other component is a flexible conductor piece. (5) the printed circuit board has an array of terminal pads proximate an edge of the printed circuit board, and the flexible conductor strip has an aligned conductor array; 5. The electrical component of claim 4, wherein the bond between the conductors is formed by passing the rotating body once across the array. (6) The electrical component according to any one of claims 3, 4, or 5, wherein the joining is performed through an intermediate for brazing l-1'' or soldering. . (7) Parts of two parts are arranged surface-to-surface in contact, and one part on the opposite side of the surface placed in the contact state
A method of permanently bonding conductive electrical components by pressing a rapidly rotating body across the surfaces of two components, thereby creating an instantaneous high energy level at the contact surfaces.