Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
2002-09-06
2004-10-19
Cuneo, Kamand (Department: 2827)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S803000, C438S613000
Reexamination Certificate
active
06807064
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention relates to an electronic component with at least one semiconductor chip, and to a method for producing the electronic component.
Electronic semiconductor chips can be connected to rewiring boards or layers and printed circuit boards to make so-called chip size packages (CSPs). The electrical and mechanical connections between the individual components can contain soldered wire connections. The soldered connections, which by now are made with lead-free solder, must be heated to temperatures of at least 240° C. This puts a considerable temperature stress on the vulnerable semiconductor components. Once the CSPs have been produced, test routines are performed for functionally testing the semiconductor chips; if the outcome is negative, the already-soldered semiconductor chips have to be replaced. Besides the effort of handling, which involves labor costs and slows down production, this also results in another high temperature stress on the components.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide an electronic component with at least one semiconductor chip and a method for producing the electronic component which overcomes the above-mentioned disadvantages of the prior art devices and methods of this general type, which furnishes a fast component connection, which can be produced economically, between a semiconductor chip, a rewiring layer and a printed circuit board that moreover enables fast replacement of an already-mounted semiconductor chip.
With the foregoing and other objects in view there is provided, in accordance with the invention, an electronic component. The electronic component contains at least one semiconductor chip, a rewiring layer connected to the semiconductor chip and has a surface remote from the semiconductor chip, a printed circuit board associated with the rewiring layer, and contact faces disposed on the printed circuit board. Flexible contacts are disposed on the surface of the rewiring layer remote from the semiconductor chip. The flexible contacts correspond with the contact faces on the printed circuit board. A flat intermediate layer solidly connects the rewiring layer to the printed circuit board.
According to the invention, the electronic component has the semiconductor chip, the rewiring layer connected to the semiconductor chip, and the printed circuit board associated with the rewiring layer. It is provided that the rewiring layer has flexible contacts, which correspond to contact faces of the printed circuit board, and that the rewiring layer is solidly connected to the printed circuit board via a flat intermediate layer.
The electronic component of the invention has the advantage that a separable component connection between the rewiring layer, with the at least one semiconductor chip mounted on it, and the printed circuit board can be produced quickly and inexpensively. Moreover, the mounting can be done with a very high throughput, without having to make soldered connections that would represent a considerable temperature stress and an unavoidable expenditure of time in processing the components. A single semiconductor chip can be mounted on the rewiring layer. However, electronic components with many semiconductor chips on a single rewiring layer are also possible. It is also possible for one or more rewiring layers to be mounted on one printed circuit board, so that optionally, very large scale integration electronic components can be achieved.
In a first embodiment of the invention, the rewiring layer, having the at least one semiconductor chip, and the printed circuit board are mounted at a defined spacing from one another. This has the advantage that the flexible contacts of the rewiring layer are placed with a defined contact to the contact faces of the printed circuit board and assure a secure electrical contact of the two components. Depending on the size of the flexible contacts, the defined spacing can advantageously be in a range from about 50 &mgr;m to 200 &mgr;m, making extremely compact structural heights of the chip size packages (CSPs) feasible.
In a further embodiment of the invention, when the rewiring layer has been mounted on the printed circuit board, the flexible contacts are prestressed. This has the advantage of a defined contact force of the flexible contacts, thus assuring a secure electrical contact between the touching faces, which are metal. The elasticity, perpendicular to the component surface, of the flexible contacts moreover assures a certain composition for unevenness and raised areas of the rewiring layer or of the printed circuit board relative to one another.
One embodiment of the invention provides that the flexible contacts protrude slightly past the flat intermediate layer between the rewiring layer and the printed circuit board, in the unstressed state. The embodiment has the advantage of a reliable connection at all times between the flexible contacts and the contact faces of the printed circuit board, since the flexible contacts are initially elastically deformed, until they mechanically impact the flat intermediate layer and thus form a reliable electrical contact.
In another embodiment of the invention, the flat intermediate layer contains a plastic, which has the advantage of simple, economical processability—for example by injection molding. Moreover, plastic acts as an electrical and thermal insulator, so that it is advantageously suitable as a touch layer, even of current-carrying regions of the semiconductor chip or of the rewiring layer.
In a further embodiment of the invention, the flat intermediate layer is embodied in multiple parts, and only at interstices between adjacent flexible contacts and/or groups of flexible contacts is it applied. This has the advantage that the flexible contacts have enough clearance for deformation at all times, without striking the intermediate layer in their elastic flexing.
One embodiment of the invention provides that the flat intermediate layer is perforated, and that flexible contacts are disposed in the interstices. This embodiment has the advantage of particular stability, because of the grid-net shaped structure formed as a result. This also makes it possible to simplify processability in a single, fast injection molding process.
In one embodiment of the invention, the flat intermediate layer is a film that is adhesive on both sides, which has the advantage of especially simple, extremely fast processability. The film can be applied in one step, immediately after which the rewiring layer can be pressed onto the printed circuit board. This makes for very fast cycle times and thus a very high throughput in production of the electronic components of the invention.
In a further embodiment of the invention, the flat intermediate layer is embodied as a one-piece perforated or multi-part base on the rewiring layer, over which a thin adhesive film is secured. This base can be applied in a simple way, for instance using a pressing technique, and has a defined thickness. The thin adhesive film applied over it then assures a solid bond between the base, which is already solidly connected to the rewiring layer, and the printed circuit board. The base can advantageously contain a polymer material, for instance, which makes it especially simple to process. As needed, the base can be in multiple parts, with the parts each disposed in interstices between flexible contacts. A one-piece version in a grid-net shaped structure is equally possible.
An alternative embodiment of the invention provides that the flat intermediate layer is embodied as a one-piece perforated or multi-part base on the printed circuit board, over which a thin adhesive film is secured. This has the advantage that compared with the above embodiment, a defective semiconductor chip can be easily removed from the printed circuit board again and replaced with an intact one.
One embodiment of the invention provides that the adhesive bond adheres more strongly to the printed circuit board than to the re
Hedler Harry
Meyer Thorsten
Cuneo Kamand
Dinh Tuan
Greenberg Laurence A.
Infineon - Technologies AG
Mayback Gregory L.
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