JPS59201486A - Method of soldering circuit element to circuit board - 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 relates to a method of soldering circuit elements to a circuit board, and more particularly, to a method of soldering circuit elements to a circuit board, and more particularly, to a method of soldering circuit elements to a circuit board, and more particularly to a method of soldering circuit elements to a circuit board, and more particularly, the present invention relates to a method of soldering circuit elements to a circuit board. A solder surface is provided on the outer surface of the circuit board where the electronic circuit elements are to be connected, and flux is applied to at least the equipment side of the circuit board.Then, the circuit elements and contact elements are placed on the solder surface, and the solder surface and The bonding procedure describes a method for forming solder connections between the contact elements of the electronic circuit element and the connections of the associated circuit board.

Conventional electronic circuit elements mounted on a circuit board are provided with a connecting wire A7 that is inserted into a hole (through contact) in the circuit board and soldered into the hole.For the purpose of saving space, , newer circuit elements omitted this connecting wire, and the contact wires, in the form of strip contacts, were formed directly on the circuit element or its casing.Rather than being inserted through a hole in the circuit board, it was simply soldered. Circuit elements are also known in which the contact elements are formed by J-shaped connecting pieces or connecting wires, which are configured to be mounted on a surface.

However, in the case of this circuit element, it is important to know how quickly and reliably the contact element can be connected to the circuit board, i.e. the adjacent solder melts a particular solder connection one or more times without damaging the location, The question arises as to whether it can be reformed.

In the known method of forming solder connections, the entire circuit board on which the through contacts are formed, for example by electroplating the inner walls of the holes formed for the through contacts, is heated by a heater plate or continuous infrared heating after the circuit elements have been mounted. Heated by a furnace. A disadvantage of this known method is that the entire circuit element is heated to the soldering temperature and it is not possible to melt only a particular solder connection without damaging adjacent circuit elements or solder connections. For example, if you want to replace a particular circuit element, you may be forced to heat all the contacts in the same manner as for example the original soldering, but soldering unrelated circuit elements may damage the area or cause other damage. There is a risk of damage in the following manner.

A method of heating with superheated steam is also known, but this method can also cause almost the same problems as described above.

It is an object of the present invention to minimize the heat load caused by soldering without damaging adjacent solder connections (so that individual solder connections on a circuit board can be easily remelted and reformed). To provide a method for quickly and reliably soldering an electronic circuit element that does not have a connecting wire or a connecting piece, or an electronic circuit element that does not have a contact element inserted into the circuit board, to a circuit board. It's about presenting.

This object is achieved in the present invention by providing the solder side with through-contact ends and, after equipping with the circuit elements, by dipping the back side of the circuit board opposite the circuit elements into a solder bath.

An important advantage of the solution according to the invention is that when immersed in the solder bath, the solder material rises under capillary action in the through contact hole to the upper solder surface and comes into contact with the contact element of the circuit element. The diameter of the through contact hole can be made very small, as long as it is large enough to allow the solder material to rise under capillary action. Therefore, the space savings obtained by downsizing the circuit elements can actually be achieved on the circuit board as well.

This can be done from the back side of the board, in which case only the initial solder connections are removed, for example by covering the back side of each circuit board with a mask with one or more windows before dipping into the solder bath. Let it melt. In this case, it does not contact the circuit elements mounted on the front side of the circuit board. During this dipping process, the solder connections covered by the mask do not melt, so they are not affected by the melting of the solder connections of a particular circuit element.

Therefore, specific circuit elements can be replaced at any time without excessive thermal stress being applied to the solder connections throughout the circuit board.

Because the solder surfaces on both sides of the circuit board are constantly connected to each other via solder material that passes through the contact holes, when remelting the solder joints, do not place a solder ring or solder around the contact holes. There is no possibility that the solder surface will peel off from the surface of the circuit board, as is the case with conventional soldering methods in which a surface is provided and only the surface of the circuit board is bonded.

Another advantage of the method according to the invention is that the connection wire A? The advantage is that both circuit elements without wires and circuit elements with connecting wires can be soldered to the circuit board in the same working order. That is, in the case of conventional connection wires for circuit elements, if they are inserted into the contact holes in the same manner as in the past, the circuit board can be immersed in a solder bath to be soldered into the individual contact holes. With the known method of soldering circuit elements from the top side of the circuit board, it is not possible to treat circuit elements with connecting wires A7 and circuit elements without connecting wires in this same manner.

If desired, waves generated in the solder bath may be used to force the solder material into the holes in the circuit board to encourage the rise of the solder material by capillary action.

Hereinafter, the present invention will be described in detail based on embodiments shown in the drawings.

In the drawings, 10 is a circuit board consisting of a plurality of layers 12. A plurality of holes or negative carrying contacts 14, at least partially covered with a conductive layer 13, pass through the circuit board 10 and serve to electrically connect conductors 16 located in each layer of the circuit board 10 to each other. This through contact 14 is located at a connection part associated with each contact element 18 of the circuit element 20. The outer end of the feed-through contact 14 is surrounded or covered by a solder ring or solder surface 22 .

A circuit board 10, manufactured in a known manner, is provided with feed-through contacts 14 and solder surfaces 22. On the equipment side of the circuit board 10,
The solder surface 22 is treated with a painted or screen printed flux. The circuit elements are then placed in a known manner on the solder surfaces provided for each element. The entire circuit board is now immersed in the solder bath 24 as shown on the side opposite the circuit elements, and the solder material is applied to the contact elements 18 of the circuit elements 20, either automatically or by generating waves of solder material. The contact element 18 of the circuit element 20 is connected to the solder surface 22 by raising it along the through contact 14 until it reaches the solder surface 22 .

For example, if it is desired to remove the illustrated circuit element 20 from the circuit board 10 independently of other circuit elements not shown, the procedure described above may be performed, but before immersing the circuit board 10 in the solder bath 24, the circuit element 20 is removed from the circuit board 10. The side of the board 10 opposite to the circuit elements is shown by a mask 26 (not shown in broken lines), and the solder material in the solder bath 24 is exposed to the solder surface 22 which is opened by a window 28 formed in the mask 26. reach.

As a result, the solder spots corresponding to this solder surface 22 melt, making it possible to remove the intended circuit element 20 without affecting the remaining solder spots on the circuit board 10. can. Remelting of the same circuit element or a new circuit element 20 can also be performed using mask 26 without affecting the remaining solder.

Another advantage of the solution according to the invention is that circuit boards with mounted and soldered circuit elements can be tested in a known manner with a test probe stand. All contact elements and all connection points of a circuit element can be mechanically scanned and inspected from the solder side.

[Brief explanation of the drawing]

The accompanying drawing is a cross-sectional view schematically showing a circuit board immersed in a solder bath with circuit elements. DESCRIPTION OF SYMBOLS 10... Circuit board 12... Layer 14... Through hole 16... Conductor 18... Contact element 20... Circuit element 22... Solder surface 24... Solder bath 26...
・Mask 28...Window patent applicant Nitzdorf Computer Akchengesellschaft--]

Claims (3)

[Claims] (1) Provide a solder surface 22 at a location for connecting an electronic circuit element 20 on the outer surface of the circuit board 10 with through contacts 14 between the two surfaces and/or between various conductors 12; Flux is applied to at least the equipment side, and then the circuit element 20 is placed on the solder surface 22 together with the contact element 18 and bonded to the solder surface, and the contact element 18 of the electronic circuit element 20 and the circuit board 1 related thereto are A method of forming a solder connection between a connection portion on a circuit board 10, comprising: placing a solder surface 22 at an end of a through contact 14; A method of forming a solder connection, which is characterized in that the opposite back side is immersed in a solder bath 24. (2) The method according to claim (1), characterized in that the soldering material is pressed onto the back side of the circuit board 10. (3) Prior to immersion in the solder bath 24, the back side of each circuit board 10 is covered with a mask having at least one window 28.
The method described in section.