Electricity: conductors and insulators – Boxes and housings – Hermetic sealed envelope type
Reexamination Certificate
2002-09-30
2004-03-30
Reichard, Dean A. (Department: 2831)
Electricity: conductors and insulators
Boxes and housings
Hermetic sealed envelope type
C174S050510, C257S687000
Reexamination Certificate
active
06713677
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a housing assembly for an electronic device and to a method for packaging electronic devices.
In semiconductor technology, semiconductor chips are provided with a housing for protection against mechanical damage and against ambient influences by various methods. In the case of machine-mountable devices, the housing also performs functions which are crucial for the further processing and mounting. The chips are encapsulated against ambient influences with a housing made of an injection-molding compound or a housing made of ceramic or a housing made of a plastic adhesive compound, also called “Globetop” encapsulation.
The art places increasing demands for housings that are inexpensive, simple to produce and machine-mountable and can be used both in the test phase of a semiconductor chip and in the mass production phase.
2. Summary of the Invention
It is accordingly an object of the invention to provide a housing assembly for an electronic component and a packaging method which overcome the disadvantages of the heretofore-known devices and methods of this general type and which provide for a housing assembly that can be produced inexpensively compared with the prior art device packages or device encapsulations and that is compatible with the production lines existing to date.
With the foregoing and other objects in view there is provided, in accordance with the invention, a housing assembly for an electronic component, comprising:
an electronic device;
an external contact carrier connected to the electronic device;
a housing frame encasing the electronic device;
at least one covering selected from the group consisting of an underside covering part and a top-side covering part;
the electronic device, the housing frame, and the covering forming interspaces therebetween; and
capillary-acting epoxy resin filled in the interspaces in a heated state via a filling-in opening, wherein the epoxy resin fills the interspaces and the interspaces are dimensioned to form capillary spaces selected from the group consisting of capillary gaps and a capillary bore.
In other words, the housing assembly for an electronic device has at least the following components:
an electronic device to be packaged (e.g. a semiconductor chip),
an external contact carrier,
a housing frame surrounding the semiconductor chip, and
an underside covering part and/or a top-side covering part, the interspaces of the components being filled in a heated state by means of a capillary-acting epoxy resin via a filling-in opening and the interspaces being dimensioned as capillary gaps or capillary holes.
The housing assembly according to the invention has the advantage that no shaped bodies whatsoever are required in the production of the housing assembly, especially as the housing assembly already represents the outer form of the housing. At most, supporting elements are necessary which keep the housing components at a distance relative to one another during the process of filling in the capillary-acting epoxy resin. In the simplest case, such a supporting element may be a plate-type chip carrier which simultaneously has the external contacts plated-on, impressed or printed-on. The chip position, i.e. the position of the active side of a chip which has the electronic components, can be chosen completely freely in the case of this housing assembly. Thus, the active side may face upward as in the case of a fingertip module and be freely accessible or be covered by a top-side covering part, as in the case of machine-mountable housing variants.
Contact-making and connection of contact areas on the semiconductor chip to external contact areas via contact pads can be carried out by means of wire bonding on the upwardly facing active area of the semiconductor chip or, as in the so-called flip-chip technique, be provided downward to corresponding contact pads on the carrier material of the external contact carrier. Consequently, the housing assembly according to the invention is distinguished by high adaptability and high flexibility in conjunction with reduced costs for mounting and assembly.
In one embodiment of the invention, the housing assembly includes a fingertip module, i.e., a fingerprint capture module or a fingertip chip sensor. Since the fingertip module must be accessible on its top side with the active semiconductor chip area, the filling-in opening is provided for the capillary-acting epoxy resin in the underside covering part. Therefore, during production, the housing assembly is positioned with the underside covering part pointing upward for the purpose of filling in the capillary-acting epoxy resin.
In a further embodiment of the invention, the underside covering part of a housing assembly for the fingertip module may include an integral edge covering. This has the advantage that the two components required, namely the external contact carrier and the housing frame, are in one piece and form a unit and, consequently, do not have to be adjusted with respect to one another during assembly.
In a further embodiment of the invention, the gap between the underside covering part of the housing assembly of a fingertip module and the semiconductor chip and between the integral edge covering and the semiconductor chip is adapted to the capillary action of the epoxy resin. This capillary action has the consequence that the uniform distribution of the capillary-acting epoxy resin in the gap is stopped if the gap exceeds a critical size. This property of a capillary-acting epoxy resin has the advantage that no additional measures whatsoever are required in order to seal capillary-acting gaps or capillary-acting holes which open toward the outer side of the housing assembly against escape of the epoxy resin.
In a further embodiment of the invention, the fingertip module has bonding connections between contact pads of the external contact carrier and contact areas on the semiconductor chip. These bonding connections can be fitted after the fixing of the chip with the aid of the capillary-acting epoxy resin to the top side of the semiconductor chip, on the contact areas arranged there, in order to connect the latter to the contact pads of the external contact carrier. To that end, the contact areas on the semiconductor chip are arranged in an edge region of the semiconductor chip which can be sealed after the introduction of the bonding connections by means of a thermoplastic potting compound with inclusion of the bonding connections.
In a further embodiment, the external contact carrier of the fingertip module is a flexible multilayer conductor strip having flat conductors which are arranged between the contact pads and external contact areas on a flexible substrate and are partly covered by an insulation layer. This embodiment has the advantage that the external contact carrier can be adapted to the spatial requirements of the place where the fingertip module is used. Moreover, it becomes possible to form the external contact carrier as flexible multilayer conductor strip in a machine mounting installation as continuous conveying strip on which the housing assembly according to the invention is to be arranged and fixed. To that end, the flexible multilayer conductor strip has corresponding openings which permit access to the active semiconductor area of the fingertip module.
In a further embodiment of the invention, the housing assembly includes a smart card module. In this embodiment, the semiconductor chip is arranged on the external contact carrier using flip-chip technology, the external contact carrier simultaneously forming the underside covering part of the smart card module and carrying both the external contact areas and the contact pads. To that end, the contact pads are arranged in a pattern which corresponds to the pattern of the contact areas on the semiconductor chip, so that the contact bumps of the semiconductor chip can be connected to the contact pads of the external contact carrier by means of flip-chip technology.
In a further embo
Fischbach Reinhard
Fries Manfred
Zaeske Manfred
Greenberg Laurence A.
Infineon - Technologies AG
Locher Ralph E.
Oliva Carmelo
Stemer Werner H.
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