Patent Application
20230081711
This application claims the priority benefit of French Application for Patent No. 2109675, filed on Sep. 15, 2021, the content of which is hereby incorporated by reference in its entirety to the maximum extent allowable by law.
The present disclosure generally concerns electronic contact connection techniques. The present disclosure more particularly applies to wire bonding techniques.
There exist different techniques enabling to connect, to one another, contacts of electronic components and/or connection pads of printed circuit boards.
Among these different techniques, the wire bonding technique is an efficient technique enabling to link with an electrically-conductive wire, preferably a metal wire, a plurality of contacts or connection pads.
It would be desirable to be able to at least partly improve certain aspects of known connection techniques and, in particular, certain aspects of known wire bonding techniques.
There is a need for a wire bonding technique adapted to more efficiently connecting connection pads.
There is a need for a wire bonding technique adapted to forming stronger connections.
An embodiment overcomes all or part of the disadvantages of known wire bonding techniques and known wire bonding technique tools.
An embodiment provides a wire bonding tool comprising at the level of one of its ends at least one protrusion.
According to an embodiment, said at least one protrusion has a rectangular cross-section.
According to an embodiment, the rectangular cross-section has a width in the range from 5 to 10 μm.
According to an embodiment, the rectangular cross-section has a length in the range from 5 to 10 μm.
According to an embodiment, the tool comprises at least two protrusions.
According to an embodiment, said at least two protrusions are parallel to one another.
According to an embodiment, said end is an end comprising an opening adapted to letting out a wire.
According to an embodiment, the tool further comprises a tubular cavity.
According to an embodiment, the tubular cavity has a round cross-section.
According to an embodiment, the tubular cavity has an oval cross-section.
According to an embodiment, the tool further comprises heating means.
According to an embodiment, the tool further comprises means for generating an ultrasound wave.
Another embodiment provides a wire bonding method using the previously-described wire bonding tool.
The foregoing features and advantages, as well as others, will be described in detail in the following description of specific embodiments given by way of illustration and not limitation with reference to the accompanying drawings, in which:
Like features have been designated by like references in the various figures. In particular, the structural and/or functional features that are common among the various embodiments may have the same references and may dispose identical structural, dimensional and material properties.
For the sake of clarity, only the steps and elements that are useful for an understanding of the embodiments described herein have been illustrated and described in detail.
Unless indicated otherwise, when reference is made to two elements connected together, this signifies a direct connection without any intermediate elements other than conductors, and when reference is made to two elements coupled together, this signifies that these two elements can be connected or they can be coupled via one or more other elements.
In the following disclosure, unless otherwise specified, when reference is made to absolute positional qualifiers, such as the terms “front”, “back”, “top”, “bottom”, “left”, “right”, etc., or to relative positional qualifiers, such as the terms “above”, “below”, “upper”, “lower”, etc., or to qualifiers of orientation, such as “horizontal”, “vertical”, etc., reference is made to the orientation shown in the figures.
Unless specified otherwise, the expressions “around”, “approximately”, “substantially” and “in the order of” signify within 10%, and preferably within 5%.
The body of the capillary of wire bonding tool 10 has a substantially elongated and tubular shape, for example, a substantially frustoconical shape, and comprises a tubular cavity 11 at its center configured to containing a bonding wire (not shown in
According to an embodiment, tool 10 comprises, at the level of its end 15, at least one protrusion 17, preferably a plurality of protrusions 17. End 15 is the end of the capillary of tool 10 which has the bonding wire coming out of it during the implementation of tool 10. In other words, end 15 is the end of the tip of tool 10. According to an example, the capillary of tool 10 and its end 15 are made of ceramic. The flared surface of the end 13 forms a lateral surface of an innermost one of the protrusions 17.
According to an example, tool 10 comprises from 1 to 3 protrusions 17. Protrusion(s) 17 are arranged at the level of end 15 to protrude from the end of the tool 10 in a direction parallel to the main direction of tool 10, the vertical direction in
Tool 10 comprises a heating element (not shown in
Tool 10 further comprises means for bonding the wire (not shown in
A tool of this type is generally attached to a mobile arm of a displacement device enabling to accurately position it above a connection pad arranged on a printed circuit board.
A bonding wire configured for use with tool 10 is made of a metal or of an alloy of metals. As an example, the wire is made of gold. The wire has a diameter conforming to the dimensions of cavity 3. As an example, the wire has a diameter in the range from 15 to 30 μm, for example, in the range from 18 to 25 μm, for example, in the order of approximately 20 μm. According to another example, the wire may have a diameter in the order of 50 μm.
More particularly,
As an example, connection pads C1 and C2 are arranged on a substrate 30, but as a variant, the contacts may be contacts of components directly arranged thereon, these components for example being bonded to a printed circuit board. Substrate 30 is, for example, a semiconductor substrate, for example made of silicon. Connection pads C1 and C2 are made of a conductive material, for example a metal or of an alloy of metals.
At the step of
At the step of
At the step of
At the step of
Wire 20 is cut, or broken, just after this second bonding step. The wire bonding method is then ended and connection pads C1 and C2 are connected to each other via a portion of bonding wire 20.
The tool heating element can then be reactivated afterwards to form a new ball at the end of wire 20. The method is then repeated as needed.
An advantage of the use of a wire bonding tool of the type of the tool 10 described herein is that it allows a better bonding by crushing of a bonding wire on a connection pad. More particularly, the tool enables to form a more robust adhesion of the bonding wire onto the connection pad.
Another advantage is that the use of a bonding tool may enable to decrease the mechanical force applied by the wire bonding tool during the crushing of the wire on the connection pad.
Further, another advantage of this embodiment is that it does not modify the conventional wire bonding method and that it can adapt on already-existing wire bonding tools.
Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these various embodiments and variants may be combined, and other variants will occur to those skilled in the art.
Finally, the practical implementation of the described embodiments and variations is within the abilities of those skilled in the art based on the functional indications given hereabove.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2109675 | Sep 2021 | FR | national |
