WO2004006333A1

WO2004006333A1 - Multi electric device package

Info

Publication number: WO2004006333A1
Application number: PCT/IB2003/002642
Authority: WO
Inventors: Wicher I.-J. Gispen; Petrus J. Lenoir; Johannus W. Weekamp
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2002-07-04
Filing date: 2003-06-24
Publication date: 2004-01-15
Also published as: AU2003239739A1

Abstract

The multi electric device package (1) comprises a first electric device (13) and a second electric device (23), which are connected to a first substrate (10) and a second substrate (20), respectively, such that the first electric device (13) is situated between the first substrate (10) and the second substrate (20). The distance (19) between the first substrate (10) and the second substrate (20) is mainly determined by a bridging element (30) situated between the first substrate (10) and the second substrate (20). The multi electric device package (1) is particularly suited to secure and obscure sensitive information contained in the first electric device (13). The apparatus (40) for reproducing information from a data carrier (41) has a signal processor (43) and the signal receiver (50) has a signal processor (52). The signal processor (43) and the signal processor (52) each comprise a multi electric device package (1).

Description

Multi electric device package

The invention relates to a multi electric device package comprising a first electric device, a second electric device, a first substrate having a first circuitry and a first surface, and a second substrate having a second circuitry and a second surface facing the first surface, the first surface and the second surface mutually having a distance, the second substrate being mechanically connected to the first substrate, the first electric device, which is situated between the first surface and the second surface, being electrically connected to the second electric device via the first circuitry and the second circuitry.

The invention also relates to an apparatus for reproducing information from a data carrier and to a signal receiver comprising such a multi electric device package.

US-B 1-6,201,266 discloses a multi electric device package described in the opening paragraph.

The known multi electric device package comprises a first electric device, which is connected to a first circuitry of a first substrate, and a second electric device, which is connected to a second circuitry of a second substrate. The second surface of the known second substrate may have a cavity. The first electric device is situated between the first substrate and the second substrate. The space available for the first electric device is determined by the mutual distance of the first surface and the second surface, which is determined by connectors mechanically connecting the first substrate with the second substrate.

In the known multi electric device package the first substrate is connected to the second substrate by means of a ball grid array (BGA) which comprises a plurality of metallic soldered joints. Usually metallic soldered joints are substantially spherical in shape. In order to prevent an electrical short circuit between mutual metallic soldered joints their mutual distance has to be larger than their diameter.

Lamination of a plurality of electric devices has been developed initially for applications where the space of the package has to be minimized, e.g., for portable electronic apparatus. In these cases multi electric device packages provides device configurations, which are thinner, smaller and lighter.

Many electronic apparatus such as, e.g., computers, set-top boxes and DVD players comprise electric devices, e.g., memory chips, which carry sensitive information such as, e.g., a serial number of the apparatus, a license number for a software program, an identification number for a program channel, or a regional code for a DVD player. For the manufacturers of these apparatus it is advantageous to use multi electric device packages to secure and obscure the electric device carrying this sensitive information.

When the sensitive information can be accessed by, e.g., monitoring electric signals between the electric device carrying sensitive information and another electric device, e.g., a signal processor, it is possible to reuse this information in other apparatus. To this end the sensitive information is received and written in, e.g., a memory device. Subsequently, this newly written memory is built into an apparatus initially not equipped with the sensitive information. This is done, e.g., by replacing the original memory device, which does not contain the secure information or by introducing the memory device to a position, which was initially unoccupied.

In recent years, there is a growing need to prevent such unauthorized replacement of the electric devices carrying sensitive information. In principle, multi electric device packaging of the kind described in the opening paragraph can provide two advantages: (1) the circuitry transporting electric signals between a first electric device carrying secure information and a second electric device can be obscured by this second electric device and the second substrate, in this way it is no longer possible to access the secure information in the way described above, and (2) the second electric device and the second substrate can be attached to the first substrate in such a way that the first electric device carrying secure information is at least partly obscured.

In many cases a variety of first devices exists which all have a similar functionality and each of which could be alternatively used in the multi electric device package. E.g., there are various memory chips of different manufacturers, which can in principle be used in combination with a particular type of the second device. Often, the second electric device, e.g., a microprocessor, is provided on a second substrate by the manufacturer of the second electric device.

In the situation described in the previous paragraph the manufacturers of multi electric device packages, in particular the manufactures of apparatus carrying sensitive information in an electric device, have a need to choose among at least a number of the different types of first electric device to use that type, which is advantageous at the time of production, e.g., cheapest or fastest to be delivered.

It is a disadvantage of the known multi electric device package that the space between the first substrate and the second substrate is limited by the connectors mechamcally connecting the first substrate and the second substrate. In the known multi electric device package a BGA is used and therefore, the distance between the first substrate and the second substrate is limited by the diameter of the metallic soldered joints, which in turn is limited by the mutual distance of the metallic soldered joints. The mutual distance of the metallic soldered joints is often limited by the second circuitry layer, which cannot be modified easily when assembling the multi electric device package. As a consequence it is not possible to accommodate a first device with a height larger than the maximum allowable diameter of the metallic soldered joints.

It is an object of the invention to provide a multi electric device package of the kind described in the opening paragraph which has a construction allowing for the presence of a first electric device selected from first electric devices of a variety of sizes and shapes.

The invention is defined by the independent claims. The dependent claims define advantageous embodiments.

The object is according to the invention realized in that the multi electric device package further comprises a bridging element situated between the first surface and the second surface, the bridging element being mechanically secured to the first substrate and to the second substrate by securing means, the bridging element and the securing means bridging the distance.

In the multi electric device package according to the invention the distance between the first surface and the second surface depends on the height of the bridging element and the securing means. The bridging element may be, e.g., a printed circuit board or a socket. Preferably, there are no connectors directly mechanically connecting the first substrate with the second substrate. The first circuitry is electrically connected to the second circuitry by, e.g., an electrical conductor which may be free of the bridging element.

It is advantageous if the bridging element comprises a third circuitry, which electrically connects the first circuitry and the second circuitry. This circuitry may comprise a layer of circuitry and a plurality of plated through holes. Alternatively, this circuitry may comprise a semiconductor substrate. This allows for the presence of a first electric device which could otherwise not be correctly electrically connected.

It is advantageous if a perpendicular projection of the first electric device onto the first surface defines a first area, a perpendicular projection of the bridging element onto the first surface defines a second area, the first area being free from the second area.

In a multi electric device package with this property a perpendicular projection of the bridging element onto the first substrate does not overlap a perpendicular projection of the first electric device onto the first substrate. As a consequence there is no portion of the bridging element between the second substrate and the first device. Therefore, the first electric device can have a height which is limited only by the distance between the first surface and the second surface.

It is advantageous if the second area laterally substantially circumferentially encloses the first area. In this geometry the first electric device is at least partly obscured by the bridging element and the securing means. It is advantageous if the bridging element is mechanically connected to the first substrate and/or the second substrate by resin. Suitable resins comprise epoxy, silicon- based resins and acrylate. When epoxy resin is used for mechanically connecting the substrates it is substantially impossible to separate the substrates without destroying them, which makes the replacement of the first electric device very unattractive, in particular when the second device is costly such as, e.g., a microprocessor.

It is advantageous if in a multi electric device package having a third circuitry the third circuitry is connected to the first circuitry and/or the second circuitry by metallic soldered joints. When metallic soldered joints are used for the electrical and mechanical connection of the substrates it is rather tedious to de-solder the connection between the substrates. In addition it is likely that the second device gets damaged during this operation, which makes the replacement of the first electric device less attractive, in particular when the second device is costly such as, e.g., a microprocessor.

It is advantageous if the signal processor of the apparatus and the signal receiver, respectively, comprises a multi electric device package according to the invention.

These and other aspects of the multi electric device package, the apparatus and the signal receiver according to the invention will be further elucidated and described with reference to the drawings, in which: Fig. 1 is a top view of a first embodiment of the multi electric device package, Fig. 2 is a cross section of the first embodiment of the multi electric device package according to II— II in Fig. 1,

Fig. 3 is a top view of a second embodiment of the multi electric device package,

Fig. 4 is a cross section of the second embodiment of the multi electric device package according to TV-TV in Figs. 3 and 5,

Fig. 5 is a top view of a third embodiment of the multi electric device package, Fig. 6 is a schematic view of an embodiment of the apparatus for reproducing information from a data carrier, and

Fig. 7 is a schematic view of an embodiment of the signal receiver. The Figs, are not drawn to scale. In the Figs., like reference numerals refer to like parts.

The multi electric device package 1 shown in Figs. 1-2 comprises a first substrate 10 having a first surface 11. In these Figs, the first substrate 10 is a printed circuit board which comprises a fiber reinforced epoxy resin. Referring now to Fig. 2 the first substrate 10 is equipped with a first circuitry 12 which is printed onto the first surface 11. In an alternative embodiment not shown the first circuitry 12 has been manufactured at least in part by supplying wires to the first substrate 10. This is in particular advantageous if the first electric device 13 placed on the first substrate 10 could not be connected to the printed part of the first circuitry 12. In yet another alternative embodiment the first circuitry 12 is printed onto the surface of the first substrate 10 which is opposite to the first surface 11. The first substrate 10, shown in Fig. 2, is equipped with a first electric device

13, which is electrically connected to the first circuitry 12. The first electric device 13, which may comprise secure information, is, e.g., a non- volatile memory chip. In another embodiment, which is not shown, it is a microprocessor having an electrical circuitry, which comprises a code in the electrical circuitry obtained, e.g., by selectively blowing up a number of fuses.

The multi electric device package 1, shown in Fig. 2, further comprises a second substrate 20 having a second surface 21 and a second circuitry 22, which is electrically connected to a second electric device 23 by metallic wires 24. The second electric device 23 and the metallic wires 24 are covered by a resin 25. It is often advantageous if the resin 25 covers the second circuitry 22 as shown in Fig. 2 to obscure and secure the data transfer to and from the second electronic device 23.

The second substrate 20 is mechanically connected to the first substrate 10 whereby the second surface 21 faces the first surface 11 and the first surface 11 and the second surface 21 mutually have a distance 19. In the space between the first surface 11 and the second surface 12, the first electric device 13 is situated.

According to the invention the multi electric device package 1 further comprises a bridging element 30, which is situated between the first surface 11 and the second surface 21. The bridging element 30 is mechanically connected to the first substrate 10 and to the second substrate 20 by securing means 35, the bridging element 30 and the securing means bridging the distance 19. In the embodiment of Fig. 2 the securing means 35 comprise metallic soldered joints 34 and 36, respectively, which are, e.g., balls of a ball grid array (BGA), and contact pins 33. In the embodiment of Fig. 4 the securing means 35 do not comprise contact pins 33, in yet another embodiment, not shown, the securing means 35 do not comprise metallic soldered joints 34 and 36. The distance 19 between the first surface 11 and the second surface 21 is now defined by the bridging element 30 and the securing means 35.

In the embodiment of Fig. 2 the first device 13 is electrically connected to the second device 23 via the first circuitry 12, the second circuitry 22, the third circuitry 32, the metallic soldered joints 34 and 36, the contact pins 33 and plated through holes 29. In another embodiment, not shown, the bridging element 30 is mechanically secured to the first substrate 10 and to the second substrate 20 by epoxy resin. In this embodiment the first circuitry 12 and the second circuitry 22 are mutually electrically connected by a set of wires and the bridging element 30 does not comprise any element, which is part of the electrical connection of the first device 13 and the second device 23.

In the first embodiment of the multi electric device package 1, shown in Fig. 1, the bridging element 30 covers the entire first electric device 13. Referring now to Fig. 2, the bridging element 30 comprises sidewalls 301 and a flat part 302, which together with the first substrate 10 form a cavity 303. Inside the cavity 303 the first electric device 13 is very well obscured and secured.

In the second embodiment of the multi electric device package 1 shown in Fig. 3-4 the bridging element 30 does not cover the first electric device 13. Referring to Fig. 3, in this embodiment a perpendicular projection of the first electric device 13 onto the first surface 11 defines a first area 14, which is free from the second area 31 formed by a perpendicular projection of the bridging element 30 onto the first surface 11. The bridging element 30 is arranged next to the first electric device 13.

The bridging element 30 shown in Fig. 4 comprises only sidewalls 301 and no flat part 302. The cavity 303 is formed by the first substrate 10, the second substrate 20 and the bridging element 30. Analogously to the first embodiment the first electric device 13 is obscured and secured inside the cavity 303. As compared to the first embodiment the bridging element 30 is less complex and less costly. Moreover, the multi electric device package 10 has a relatively small height.

In the second embodiment, the cavity 303 is not entirely closed by the bridging element 30, which consists of two separate parts 304. As compared to the first embodiment and the third embodiment to be discussed below this embodiment employs a relatively small, simple and cheap form of the second substrate 30. In an alternative embodiment, not shown, the bridging element 30 consists of a single part such as a U-shaped substrate, which does not close cavity 303, but allows for the access of a part of the first electric device 13, which may be advantageous in some situations.

In the second embodiment the first electric device 13 is further secured by mechanically connecting the second substrate 20 and the bridging element 30 by epoxy resin 37, shown in Fig. 3. The first electric device 13 is secured even better by mechanically connecting the first substrate 10 and the bridging element 30 by epoxy resin 38, shown in Fig. 3. The connections secured by the epoxy resin are so stable and firm that there is a reasonable chance that an attempt to remove the second substrate 20 will destroy the second electronic device 23.

A top view of the third embodiment is shown in Fig. 5. A cross section according to IV-IV in Fig. 5 is shown in Fig. 4. In the third embodiment the cavity 303, formed by the first substrate 10, the second substrate 20 and the bridging element 30 is closed. This is achieved by the bridging element 30 which has a shape such that the second area 31 defined by a perpendicular projection of the bridging element 30 onto the onto the first surface 11 laterally substantially circumferentially encloses the first area 14, which is defined by a perpendicular projection of the first electric device 13 onto the first surface 11, shown in Fig. 5.

The multi electric device package described above is used to secure sensitive information in apparatus 40 for reproducing information from a data carrier 41 as is shown schematically in Fig. 6. The apparatus 40 and the data carrier 41 can be, e.g., a compact disk (CD) player and a compact disk, a digital video disk (DVD) player and a digital video disk, or a digital video disk recorder (DVD RW) player and a recordable digital video disk, but the invention is not limited to these types of apparatus 40 and data carriers 41. Alternatively, the data carrier 41 can be a magnetic data carrier such as, e.g., an audiotape or videotape.

The apparatus 40 for reproducing information from a data carrier 41 according to the invention comprises an information reading means 42. For a CD player and a DVD player the information reading means 42 is a light source and a light detector. They are used to optically read out the data carrier 41 by generating an information signal, which comprises information stored on the data carrier 41. Alternatively, the apparatus 40 can be designed to reproduce information from a data carrier 41, which is a magnetic data carrier such as, e.g., an audio tape or a video tape. In this case the information reading means 42 is a magnetic head, which generates an electrical type of information signal from the magnetically stored information on the data carrier 41.

The apparatus 40 for reproducing information from a data carrier 41 according to the invention further comprises a signal processor 43 for processing the information signal. hi many cases the information signal cannot be reproduced directly because it is encrypted or encoded. In, e.g., a DVD player the information signal often has to be processed by a signal processor 43, which comprises the correct regional code. In this way it is assured that the data carrier 41 can be reproduced only by a certain subset of all existing apparatus 40 potentially capable to reproduce the information. Alternatively, it is possible to encrypt the information on data carrier 41 in such a way that it can be reproduced by only one specific specimen of all apparatus 40. This can be advantageous for, e.g., data carriers 41, which carry information for executing a computer program which is to be reproduced only on one single machine.

After processing the information signal by the signal processor 43 such that it can be reproduced, the processed signal is provided at an output terminal 44, which is to be connected to, e.g., an audio or video display unit.

In current systems there is a strong need to prevent that the data carrier 41 is reproduced by apparatus 40, which were initially designed not to reproduce this information. Initially, these apparatus 40 do not comprise the required signal processor 43 because they do not comprise, e.g., the correct regional code or the required user authorization. In many cases it was possible to simply replace those parts of the signal processor 43, which comprise the secure information, e.g., by replacing a memory chip. This way of unintended use can be prevented by using a signal processor 43, which comprises secure information secured by a multi electric device package 1 as described above. The multi electric device package described above is used to secure sensitive information in signal receiver 50 as is shown schematically in Fig. 7. The signal receiver 50 can be, e.g., a set top box or a television unit, but the invention is not limited to these types of signal receiver 50. The signal receiver 50 according to the invention comprises an input terminal

51 for receiving an incoming signal. The incoming signal may be provided via, e.g., a cable network or a terrestrial electro-magnetic signal.

The signal receiver 50 further comprises a signal processor 52 for processing the incoming signal. In many cases the incoming signal cannot be reproduced directly because it is encrypted or encoded. In many applications such as, e.g., pay per view or pay channels, the incoming signal often has to be processed by a signal processor 52, which comprises the information necessary to decode the incoming signal such that it can be reproduced by a display unit, not shown.

After processing the information signal by the signal processor 52 such that it can be reproduced, the processed signal is provided at an output terminal 53, which is to be connected to, e.g., an audio or video display unit.

In current systems there is a strong need to prevent that the incoming signal is reproduced by a signal receiver 50, which initially was designed not to reproduce this information. Initially, this signal receiver 50 does not comprise the required signal processor 52 because it does not comprise the required secure information for data processing. In many cases it was possible to simply replace those parts of the signal processor 52, which comprise the secure infoπnation, e.g., by replacing a memory chip. This way of unintended use can be prevented by using a signal processor 52, which comprises secure information secured by a multi electric device package 1 as described above. The multi electric device package 1 comprises a first electric device 13 and a second electric device 23, which are connected to a first substrate 10 and a second substrate 20, respectively, such that the first electric device 13 is situated between the first substrate 10 and the second substrate 20. The distance 19 between the first substrate 10 and the second substrate 20 is determined by a bridging element 30 situated between the first substrate 10 and the second substrate 20. The multi electric device package 1 is particularly suited to secure and obscure sensitive information contained in the first electric device 13. The apparatus 40 for reproducing information from a data carrier 41 has a signal processor 43 and the signal receiver 50 has a signal processor 52. The signal processor 43 and the signal processor 52 each comprise a multi electric device package 1. It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of other elements or steps than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.

List of reference numerals

I multi electric device package 10 first substrate

I I first surface 12 circuitry element

13 first electric device

14 first area

19 distance

20 second substrate 21 second surface

22 second circuitry element

23 second electric device

24 metallic wires

25 resin 29 plated through holes

30 bridging element

31 second area

32 circuitry element

33 contact pins 34 metallic soldered joints

35 securing means

36 metallic soldered joints

37 epoxy resin, connecting the first substrate and the bridging element

38 epoxy resin, connecting the second substrate and the bridging element 39 contact pins

40 apparatus for reproducing information from a data carrier

41 data carrier

42 information reading means

43 signal processor 44 output terminal

50 signal receiver

51 input terminal

52 signal processor

53 output terminal 301 side walls

302 flat part

303 cavity

304 separate part of bridging element 30

Claims

CLAIMS:

1. A multi electric device package comprising: a first electric device; a second electric device; a first substrate having a first circuitry and a first surface; and - a second substrate having a second circuitry and a second surface facing the first surface, the first surface and the second surface mutually having a distance, the second substrate being mechanically connected to the first substrate, the first electric device, which is situated between the first surface and the second surface, being electrically connected to the second electric device via the first circuitry and the second circuitry, characterized in further comprising a bridging element situated between the first surface and the second surface, the bridging element being mechanically secured to the first substrate and to the second substrate by securing means, the bridging element and the securing means bridging the distance.

2. A multi electric device package as claimed in claim 1 characterized in that the bridging element comprises a third circuitry, which electrically connects the first circuitry and the second circuitry.

3. A multi electric device package as claimed in claim 2, characterized in that the third circuitry comprises a plurality of mutually electrically insulated electrical connections electrically connecting the first circuitry and the second circuitry.

4. A multi electric device package as claimed in claim 1 characterized in that a perpendicular projection of the first electric device onto the first surface defines a first area, a perpendicular projection of the bridging element onto the first surface defines a second area, the first area being free from the second area.

5. A multi electric device package as claimed in claim 4 characterized in that the second area laterally substantially circumferentially encloses the first area.

6. A multi electric device package as claimed in Claim 1 characterized in that the bridging element is mechanically connected to at least one of the first substrate and the second substrate by resin.

7. A multi electric device package as claimed in Claim 2 characterized in that the third circuitry is connected to at least one of the first circuitry and the second circuitry by metallic soldered joints.

8. An apparatus for reproducing information from a data carrier comprising: an information reading means for reading information from the data carrier and generating an information signal; a signal processor for processing the information signal to produce a processed signal; and - an output terminal for delivering the processed signal; characterized in that the signal processor comprises a multi electric device package, which comprises:

- a first electric device;

- a second electric device;

- a first substrate having a first circuitry and a first surface; - a second substrate having a second circuitry and a second surface facing the first surface, the first surface and the second surface mutually having a distance, the second substrate being mechanically connected to the first substrate, the first electric device, which is situated between the first surface and the second surface, being electrically connected to the second electric device via the first circuitry and the second circuitry; and - a bridging element situated between the first surface and the second surface, the bridging element being mechanically secured to the first substrate and to the second substrate by securing means, the bridging element and the securing means bridging the distance.

9. A signal receiver comprising: an input terminal for receiving an incoming signal; a signal processor for processing the incoming signal to produce a processed signal; and an output terminal delivering the processed signal, characterized in that the signal processor comprises a multi electric device package, which comprises:

- a first electric device;

- a second electric device; - a first substrate having a first circuitry and a first surface;

- a second substrate having a second circuitry and a second surface facing the first surface, the first surface and the second surface mutually having a distance, the second substrate being mechanically connected to the first substrate, the first electric device, which is situated between the first surface and the second surface, being electrically connected to the second electric device via the first circuitry and the second circuitry; and

- a bridging element situated between the first surface and the second surface, the bridging element being mechanically secured to the first substrate and to the second substrate by securing means, the bridging element and the securing means bridging the distance.