Semiconductor device manufacturing: process – Packaging or treatment of packaged semiconductor – Insulative housing or support
Reexamination Certificate
2002-02-05
2004-01-13
Zarabian, Amir (Department: 2822)
Semiconductor device manufacturing: process
Packaging or treatment of packaged semiconductor
Insulative housing or support
C438S118000, C438S127000, C438S107000
Reexamination Certificate
active
06677187
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a novel electrical or electronic component provided with a sealed encapsulation system. It also relates to the process allowing it to be produced.
The field of the invention therefore relates more particularly to components and microcomponents, also having electronic chips, but also to microsensors, microactuators, etc.
BACKGROUND OF THE INVENTION
These microcomponents are conventionally deposited on a substrate of suitable nature, for example of the semiconductor (monocrystalline silicon, sapphire, etc.) type for electronic components. A number of electrically conducting tracks radiate from this microcomponent, towards the periphery of the substrate, so as to allow not only electrical supply to the component, if required, but also the processing and exploitation of the signals that it is called upon to generate, or even the control of the functions that it incorporates. Sometimes, a protective casing or cover is added to this component, suitable for preventing the problems inherently associated with impacts, with corrosion, with electromagnetic interference, etc., the said cover being attached, for example, by adhesive bonding. This cover may furthermore incorporate a window transparent to radiation to be detected by the said component or else a lens for focusing the said radiation onto the component.
Some of these microcomponents require for their operation to work under vacuum or in a controlled atmosphere (pressure, inert gas(es), etc.), or in a sealed manner with respect to the ambient atmosphere. Consequently, the aforementioned casing or cover is used so as to define a cavity above the said component, containing the suitable controlled atmosphere or the vacuum. The two technical concerns to be taken into consideration are therefore:
firstly, the hermeticity of the cover-component bond, intended to isolate the said component from the external agents, independently of the nature of the atmosphere then imprisoned in the volume thus defined;
secondly, the controlled nature of the atmosphere confined in the said volume, requiring that this atmosphere be distributed within this volume prior to sealing the cover onto the component.
Up to the present time, various techniques have been employed to thus allow the said electronic component to be encapsulated in a sealed manner. Among these, as described, for example, in the documents WO 95-17014 and GB-A-2,310,952, is the use of a cover or lid, which is aligned with the support provided with its electronic component and which is soldered around the entire periphery of the said support. This soldering or sealing conventionally produces a metal/metal junction typically involving a soldered joint made of indium or of a tin/lead alloy.
Conventionally, this technique is carried out in two steps: it consists in aligning the cover with respect to the component, both being within a suitable enclosure so as to provide a controlled atmosphere or, if this is not the case, a vacuum chamber, depending on the atmosphere desired, and then in sealing the said cover onto the component using technologies perfectly known to those skilled in the art.
It may be readily appreciated that, since a multiplicity of these operations has to be carried out, or a multicomponent support has to be employed, the equipment intended to carry out these operations becomes very complex and very expensive to operate, given that all these operations must be conducted within the enclosure for maintaining the controlled atmosphere or for maintaining the vacuum, as already mentioned.
Production of such microcomponents requires increasing use of techniques similar to those in microelectronics, the said components being fabricated in a collective manner. However, these microcomponents fulfil increasingly sophisticated and complex functions requiring a corresponding increase in the connection technology intended to allow them to be used.
This is because these microcomponents require a large number of electrical inputs and outputs so as to make it possible, on the one hand, for them to operate and, on the other hand, for their effects to be exploited. This number of inputs and outputs requires an equal number of electrically conducting tracks, which tracks fan out towards the periphery of the support, because of a corresponding number of connection pads around the outside, leading as it were to a considerable increase in the area occupied just by the connection system. Paradoxically, the advances made in microelectronics make it possible to reduce the active part of the component proper. In other words, a significant part of the high-performance, and therefore expensive, material used, namely the substrate bearing the component, is assigned for the sole purpose of receiving the connection tracks.
Consequently, it may be readily appreciated that collective fabrication loses its effectiveness and that, in some cases, the superfluity of connections no longer makes it possible for them to be made on a single level. In addition, when a welded casing is required, the connections must be protected from the solder bead by the use of an insulating layer, generally called a passivation layer.
In order to cope with this increase in connections, it has been proposed to produce the stack of several connection levels by separating the said levels by an insulating passivation layer. However, although this passivation technique makes it possible to solve the problem at the immediate level of the component itself, it cannot, of course, deal with the solder pads intended for making the external connections. Furthermore, although this passivation technique is relatively well controlled, it does have quite a number of deficiencies, such as leaks, short circuits, etc., which affect the efficiencies. Finally, and above all, it involves additional steps in the production of the microcomponents and furthermore generates a larger amount of scrap since each step is associated with a not insignificant scrap level, consequently affecting the overall production cost of such microcomponents.
It has also been proposed, still with the objective of coping with this increase in connections, to transfer at least some of these connections to the protective cover or casing. Thus, in document EP-A-0,609,062, the cover includes several conducting tracks produced on its external face and electrically connected to the electronic component located inside the volume defined by the support/cover assembly via conducting penetrations. These conducting penetrations extend into the thickness of the said cover and are solid, so as to ensure sealing within the aforementioned volume.
Thus, although it becomes possible to increase the amount of connections by this means, the problem associated with confining a controlled atmosphere or a vacuum within the volume defined by the support/cover assembly still remains, especially in terms of simplicity of the installation and given the manufacturing cost of the components thus produced. The drawbacks here are in fact the same as those associated with the cover used in document WO 95/17014.
BRIEF SUMMARY OF THE INVENTION
The objective of the present invention is to solve these two main problems by proposing a device and a technology which are capable of significantly increasing the connection capacity of the component, especially for cases in which the severe environmental constraints dictate it, while still allowing effective encapsulation of the said component. Furthermore, the aim of the invention is, secondarily, to eliminate the need for passivation. However, in cases where there is a great need for connections, the invention makes it possible to provide both a standard level of connections on the substrate, within this passivated scenario, and a second level of connections on the casing.
This electrical or electronic component with sealed encapsulation comprises:
a support intended to house one or more electrical or electronic components from which electrically conducting tracks radiate towards the periphery of the said support; a
Cardona Victor A.
Duong Khanh
Heslin Rothenberg Farley & & Mesiti P.C.
Societe Francaise de Detecteurs Infrarouges-Sofradir
Zarabian Amir
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