Active solid-state devices (e.g. – transistors – solid-state diode – Encapsulated
Reexamination Certificate
1997-10-28
2001-01-09
Potter, Roy (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Encapsulated
C257S433000, C257S692000
Reexamination Certificate
active
06172425
ABSTRACT:
TECHNICAL FIELD
The present invention relates to encapsulation of or packaging, with a resin or plastic material, optical transmitter and receiver modules comprising optocomponents on silicon substrates and generally encapsulated optoelectrical components and methods for the manufacture thereof.
BACKGROUND
Encapsulated optocomponents with associated wave guides, connection devices, etc. are at present expensive, which is an obstacle for a more widespread introduction of the optical communication technology. One of the major reasons for the high component cost is the extreme requirements on mechanical precision in the alignment of an optoelectronic component with a waveguide and of a waveguide in a component with another waveguide. The mounting methods of today do not allow electronic circuits to be contained or housed, in a functional and efficient manner, in the package and/or be mounted efficiently together with the optoelectronic component on a circuit board.
Having access to a common “micro construction method” for optical and microelectronic devices the conditions would be improved in order to allow fabrication of optical transmitter and receiver modules at a low cost, thereby opening new applications and markets for optical communication.
At present an intensive development work within the microstructure technology is pursued in order to achieve a possible way of positioning devices with an accuracy of the magnitude of order of one micrometer. One of the aims of this work is to replace the costly details, which are today used in the mounting of optocomponents, with mass produced details of for instance silicon.
In parallel there is a development towards more efficient methods for mounting and encapsulating integrated optical devices. One obvious development path is the use of polymer films, usually polyimide films, for this object. Since production of conductive leads using coating and etching can be carried out on such films and sandwich constructions having several layers comprising electrical conductors and ground planes (“multilayer technique”) are used, making impedance matching possible, several chips can be mounted together with each other having no additional demands on substrates or base materials. Moreover, when encapsulated with resin such a polymer film can take over the function of the traditional lead frame made of thin metal plate. Metallic or possibly metallized connection legs may protrude from the capsule wall from the carrier film in order to accomplish the electrical connection of the electronic circuits to the exterior. Also exterior metallized surfaces like those used in TAB-mounting can be present.
Flexible resin tape having lead portions can be used in an electronic multichip package as disclosed in U.S. Pat. No. 5,245,215. The flexibility of the tape is primarily used for allowing a dense packing of the chips.
In the International patent applications PCT/SE95/00281, filed on Mar. 20, 1995, PCT/SE95/01232, filed on Oct. 19, 1995, and PCT/SE95/01233, filed on Oct. 19, 1995 for the same applicant/assignee methods for encapsulating optoelectrical components with resin or plastic materials at a low cost are described. The methods rely on the fact that a substrate for hybrid mounted optocomponents is positioned with a high accuracy in a mould cavity to be overmoulded with plastics. The optocomponent is encapsulated by means of transfer moulding, whereby an optical interface in the capsule wall is obtained simultaneously by means of V-grooves on the substrate and guide pins in the mould. An electrically conducting lead frame can be used for establishing electrical contact with the electronic circuits. The lead frame usually consists of a punched or etched metal detail, for instance a thin copper or aluminium sheet.
Simultaneous encapsulation, with plastics, of optocomponents and electronic circuits with a positioning of waveguides and optoelectrical components on substrates of silicon is previously known.
Thus, in the published European patent application EP-A1 0 600 645 an optoelectronic module encapsulated with plastics and of SIP type (“Single In-line Package”) is disclosed comprising electronic components and optocomponents placed on a silicon substrate.
In the published European patent application EP-A2 0 596 613 a coupling module for coupling optical fibres 6 to an “optical unit”, or rather to an “electronic part” through an “optical unit” is described. The optical unit may comprise a base 13 of possibly silicon having electrodes and microlenses 4
a
and photodetectors 4, see FIGS. 6
a
-7
b.
The optical unit is connected to the electronic part, which can be an integrated semiconductor circuit, for instance by means of wire bonding between the electrodes on the support base plate 13 and conductive areas 9
a
on the electronic part 9 (FIGS. 5
a
and 5
b
). However, this coupling module is not encapsulated with plastics.
SUMMARY
It is an object of the invention to provide an encapsulated optocomponent and a method for manufacturing it, which allow electronic signal and driver circuits to be accommodated in the capsule in a functional and efficient manner.
It is another object of the invention to provide an encapsulated optocomponent and a method of manufacturing it, which allow electronic circuits to be placed together with the optoelectronic component on a circuit board in a simple and functional way.
These objects are achieved with the invention, the scope and characteristics of which appear from the appended claims.
Hence, in one embodiment, in a manner functional for encapsulation with plastics, also electrical circuits such as for instance receiver/driver electronic circuits can be placed inside the capsule. Hereby more compact modules can be obtained by the fact that the entire encapsulated component occupies less space on the circuit board, and that standardized electrical interfaces to the encapsulated optomodule can be obtained. The designer of the circuit board does not need to particularly consider the fact that the capsule contains optocomponents when designing a new circuit board. The short distance between the electronic circuits and the optoelectrical converter provides short current paths and thereby a possibility for high modulation speeds.
If the substrate or base plate mentioned above in connection with the state of the art, that is often provided in the shape of a silicon plate, in addition to the optocomponents is also to contain the necessary electronic devices, it becomes considerably larger, as is obvious from the disclosure in the above mentioned European patent application EP-A1 0 600 645. This will make the positioning of the base plate in the mould cavity more difficult, since larger forces will be required in order to maintain the substrate in the exactly correct position. This is particularly evident in filling a mould cavity with resin for the encapsulation of the component, since large forces will then act on the substrate and can move it from its accurately determined position. The substrate in the shape of a silicon plate is also comparatively expensive as counted per unit area, due to the often extensive processing technology used in fabricating it, and then one of course aims at as small substrates as possible.
For these reasons the electronic circuits are mounted on a special carrier or base plate, which is mechanically separated from a carrier or base plate for the optocomponent or is at least not rigidly connected to the carrier or base plate of the optocomponent.
It can also be desirable to provide a certain modularity between optocomponents and electronic components due to test methods and changes in different steps in the manufacture of carriers for the components and in the encapsulation, which can also be obtained by providing separate carriers or carrier portions for optical components and purely electrical units respectively.
One such optocarrier can be used, which is hybrid type and is known from the above described prior art, see the schematic perspective view in
FIG. 1
that is a relatively small hi
Bakszt Josef
Eriksen Paul
Steijer Odd
Burns Doane Swecker & Mathis L.L.P.
Potter Roy
Telefonaktiebolaget LM Ericsson (publ)
LandOfFree
Encapsulation of transmitter and receiver modules does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Encapsulation of transmitter and receiver modules, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Encapsulation of transmitter and receiver modules will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2443845