WO2013045215A1

WO2013045215A1 - Electronic assembly, printed circuit board and method

Info

Publication number: WO2013045215A1
Application number: PCT/EP2012/067128
Authority: WO
Inventors: Christina Schindler; Jörg ZAPF
Original assignee: Siemens Aktiengesellschaft
Priority date: 2011-09-26
Filing date: 2012-09-03
Publication date: 2013-04-04
Also published as: DE102011083419A1

Abstract

An explanation is given of an electronic assembly, containing: - a printed circuit board, on or in which at least two conductor tracks or a multiplicity of conductor tracks are arranged, - at least one electronic component or a multiplicity of components forming an electronic circuit arranged on the printed circuit board, - a conductor track arrangement covering or surrounding the circuit, - and a monitoring circuit, the inputs of which are electrically conductively connected to the conductor track arrangement, - an electrically insulating insulation layer on side surfaces of the component or on side surfaces of the components, and wherein the conductor track arrangement is arranged on the insulation layer.

Description

description

The invention relates to an electronic subassembly, a printed circuit board and a method. The electronic module contains a printed circuit board on or in which at least two printed conductors or a plurality of printed conductors are arranged. At least one electronic component or typically a plurality of components form an electronic circuit arranged on the printed circuit board.

Electrical circuits may include security-related Informati ^¬ tions and must therefore be protected from external manipulation. Attempts to manipulate the circuit electrically must be taken into account as well as chemical or mechanical manipulations, eg by drilling or

Laser ablation. Therefore, the circuit is combined with a control unit, which results in irrevocably deleting security-relevant data in the event of an external manipulation. This protection must be as easy as possible to be integrated into the manufacturing process of the circuit and may not have a lot of space, especially in miniaturized circuits.

Electrical circuits could be protected by means of Bohrschutzfolien from external manipulation. After preparation, the assembly would be ^¬ packaged three-dimensionally in a ver Bohrschutzfolie. The foil would carry electrical structures that are connected to the assembly and, if damaged, result in deletion of safety related data. Disadvantages would be the sensitivity of the metallic structures on the anti-drilling foil and therefore the low mechanical stability, the packaging process, which deviates from standard electronic manufacturing processes, and the size of the packaging.

Alternatively, the protection against manipulation could take place via a housing made of metallically structured circuit carriers. gene, which are also connected to the module to be protected. This variant would be mechanically more stable and would also allow the use of standard manufacturing processes. However, the variant would not be suitable for miniaturized structures and would also be cost-intensive.

Thus, there is a need for a further assembly that is protected against unauthorized access. The assembly should be easy to manufacture.

This object is achieved by an assembly according to claim 1 ge ^¬ . Further developments are specified in the subclaims, the following description and the drawings. The module may include a circuit arrangement surrounding or covering the circuit arrangement and a monitoring circuit whose inputs are electrically conductively connected to the conductor arrangement. The electrically insulating insulating layer can rest on side surfaces of the component or on side surfaces of the components. The conductor arrangement can be arranged on the insulating layer.

The components preferably generate on the circuit board:

- height differences greater than 50 microns, e.g. flip-chip integrated circuit (ball

Grid Array or similar), or

- greater than 200 microns, or

greater than 400 microns, e.g. SMD (Surface Mounted Device).

A method for producing the assembly does not require any additional special foils, in particular without special foils which already contain conductor tracks. Many of the required processes are also common in printed circuit board manufacturing and thus no new machines need to be purchased in this regard. The typical height differences prevent or complicate the use of prefabricated films, because then conductor breaks or conductor cracks may occur. However, the assembly can be made with high reliability, if the insulating layer and the conductor ^arrangement are applied separately from ^¬ each other, resulting in the abutment of the insulating layer on the side surfaces of the components, in particular on opposite side surfaces of a component or on the opposite side surfaces of the respective component. In particular, the insulating layer is also applied to all side surfaces of a component or all components. The generated by the components to the PCB Hö ^¬ henunterschiede are preferably less than 1 mm, less than 2 millimeters, or less than 3 millimeters.

In particular, the assembly contains no compensation films that would have to be punched out specifically for each type of assembly, and would be used separately. A Ausgleichsfo ^¬ lie would ^abut in the presence of a certain game, for example, always only on a side surface of a component and not on other side surfaces of the device. Certainly would not be the spacer film from opposite ^¬ Be tenflächen a component, as is the case with the invention.

The electrically insulating insulating layer can be arranged directly on the components. Preferably, the iso ^¬ lierschicht contains only one layer. Alternatively, the insulating layer ^¬ contains several insulating layers.

The conductor arrangement can be arranged directly on the insulating layer. The conductor track arrangement includes zweckmäßi ^¬ gerweise only one metal layer or two metal layers of different material composition.

The insulating layer can also be arranged on the side of the printed circuit board abge ^¬ turned on the component or on the components. This structural feature is the result of ner manufacturing in which the insulating layer is applied separately from the conductor arrangement, in particular by Ver ^¬ casting, dipping or laminating. The insulating layer may be arranged on the components so that at a side facing away from the component of the insulating layer also height differences greater than 50 microns ^¬ meter or greater than 200 microns or greater than 400 microns occur. The conductor track arrangement can be arranged on the insulating layer, wherein differences in height greater than 50 micrometers or greater than 200 micrometers or greater than 400 micrometers also occur at the track arrangement. Thus, the insulating layer compensates for the height differences in this variant, or only partially. On the other hand, an insulating layer with a constant thickness can be used ^¬ , as is the case with films. The insulating layer may be a plastic film or ent ^¬ hold. A plastic film can provide ^¬ easily Herge and simply applied to a topography ^¬ to, eg. Using vacuum or pressure and temperature. Because the plastic film contains no tracks, it is particularly adaptable to the topography. Is typical when using a film, that the insulating layer does not distinguish between component and circuit board befin ^¬ det. The insulating layer may also be a cast onto the circuit board layer, which was then cured. It is then typical that the material of the insulating layer also flows between the component and the printed circuit board and is thus arranged there.

The differences in height are compensated here by the use of insulating layers applied in the flowable state, so that a surface of the insulating layer, for example, height. has differences that are smaller than 50 microns, or are at least 50 percent smaller than a topography generated by the compo ^¬ ment or by the components. The reduced or leveled topography facilitates the application of the conductor track arrangement, in particular for small structural widths of the conductor tracks of less than 50 micrometers. By casting or dipping larger differences in height between PCB and components can be compensated, in particular height differences greater than 200 Mikrome ^¬ ter but less than 3 millimeters, less than 2 millimeters or even less than 1 millimeter.

In this embodiment, the insulating layer can be flattened towards its edge, for example by running a casting compound or immersion liquid or by using a specially designed mold. The flattening at the edge facilitates the application of the track arrangement, because there is no step.

The printed conductors of the printed conductor arrangement can preferably be arranged in an area which corresponds to the entire area of the printed circuit board or at least 90 percent of the printed circuit board or the area of the printed circuit board to be protected. Ins ^¬ particular the interconnects of the interconnect arrangement can be arranged meander-shaped. Meandering here means that the conductors change their direction several times by, for example, 180 degrees. However, instead of meandering, other waveforms may be used, such as helical courses in which a center is orbited with a continuously increasing radius.

The area to be protected contains the meander or several mä ^¬ other including ^gaps that have the same width as the meander or in the range of 0.5 to

2.0 of this width are. The meandering or spiral tracks change their ohmic resistance when damaged. was particularly strong, so that an unauthorized intervention can be detected more easily.

The insulating layer may be a first insulating layer and the wiring arrangement may be a first wiring arrangement. In addition, there may be a second insulating layer on or even on the first trace arrangement. On or at the second insulating layer a second Leiterbahnanord ^¬ voltage may be arranged, which is connected to the monitoring circuit or to a further monitoring circuit.

The first insulating layer may contain the same material as the second insulating layer or another material. The layer thicknesses of both layers may be the same or different.

The first wiring arrangement may contain the same material as the second wiring arrangement or another material. The layer thicknesses of both interconnects may be the same or different.

The conductor tracks of the two conductor path arrangements meander derförmig results in a particularly high degree of protection, especially if the meander of the two conductor path arrangements learning with latera- offset are arranged to each other so that there is at top ^¬ view of the conductor arrangement, no more area in which only intermediate spaces lie, so that there would be an unauthorized access to the circuitry would be facilitated. The interconnects of the track array may have a width in the range of 1 micron to 100 microns, preferably a width in the range of 5 microns to 100 microns. The same dimensions apply to the distances between adjacent sections of printed conductors of the printed conductor arrangement.

The printed conductors of the printed conductor arrangement can be more than 1 micrometer thick. The layer thickness can be less than 100 Be micrometer. By a sufficient layer thickness of the conductor tracks is achieved that the resistance changes greatly in case of damage to the conductor arrangement. In addition, a circuit board having a conductor layer be ^¬ dripped, containing at least one conductor track with MAE anderförmigem or spiral-shaped course in the area of the entire printed circuit board or in a protected area. The underside, ie one side of the printed circuit board that is not populated, can thus be easily protected against unauthorized interference. The protective metal layer can be easily produced in the manufacture of the circuit board.

The interconnect layer may be a first layer, wherein the Lei ^¬ terplatte includes a second interconnect layer containing in the region of the entire circuit board at least one further interconnect with meandering or spiral course. The protective effect can be increased in a simple way.

The conductor track of the first interconnect layer can be arranged with lateral offset to the second interconnect layer, so that the protective effect is further increased. The printed circuit board offers in particular with the conductor track arrangement of the module an all-round protection against interference from above and from below.

Also affected is a method of manufacturing an assembly:

- On a populated circuit board, a wiring arrangement is arranged separately without simultaneous placement of an insulating layer. Thus, the technical effects given above for the assembly also apply to the process. In particular, no special films need to be used on which already are arranged. Furthermore, for example. A distance ^¬ film is not required.

At least one component or Kings ^¬ nen electronic components can be arranged on the circuit board, wherein an Iso ^¬ lierschicht is applied to the component or to the components. On the insulating layer ei ^¬ ne electrically conductive layer is applied. The electrically conductive layer is structured after application to the insulating ^¬ layer to the ^wiring arrangement.

Also for this method, the technical effects given above for the assembly apply. The insulating layer can be applied over the entire surface. Likewise, the electrically conductive layer can first be applied over the entire surface and then patterned.

At least one conductor track of the conductor track arrangement can be connected to a monitoring circuit arranged on the printed circuit board, which blocks the module against unauthorized access

Protects access. The monitoring circuit cancels preference ^¬ as safety-related data in a memory of the construction ^¬ group, if an unauthorized operation is detected. Deleting in particular, by overwriting with ei ^¬ nem specified date.

The insulating layer can be applied as a film. This is a particularly simple process because no liquids need to be used. It can be used self-adhesive film. Alternatively, an additional adhesive may be used, which is applied to the film and / or on the circuit board, shortly before Ver ^¬ bind, for example. Less than 10 minutes before. Many films are already coated with an adhesive layer, which only un ^¬ ter pressure and temperature cures.

The film can be applied with overpressure or underpressure and / or with over-temperature. The pressure or the temperature here are based on room pressure or room temperature in a production room and are in particular 1 bar and 20 degrees Celsius. The application of the film can take place, for example, in a so-called autoclave, ie in a chamber whose internal pressure and its temperature are adjustable.

The overpressure may, for example, be in the range of 2 bar to 30 bar. The temperature may be, for example, in the range of 80 degrees Celsius to 190 degrees Celsius, in particular in the range of 100 degrees Celsius to 150 degrees Celsius.

Alternatively, however, the insulating layer can also be cast, spin-coated or applied by immersion. These are also methods that are also easy to perform and that lead to an additional height compensation. The drying of the still liquid or viscous insulating layer may ^¬ SUC gene by means of an additional heat treatment step, which for example takes place at a temperature ranging from 50 degrees Celsius to 200 degrees Celsius. Potting layers can be made harder than films, for example with a Shore hardness in the range of 40 to 90.

The insulating layer may be in contact regions ge ^¬ opens by means of laser. The laser beam of the laser penetrates the insulating layer, for example, only at two points or more than two points, but preferably at less than 20 points. This makes lasing very fast. Alternatively, however, a photolithographic process may be used to penetrate the insulating layer.

The wiring arrangement can be easily applied by vapor deposition or sputtering, by electroplating or by both vapor deposition or sputtering and plating. By vapor deposition or sputtering a mechanical adhesion-improving layer is verbes ^¬ example. Applied or a base coat, which can be used for an electroplating method. Typical materials here are titanium, tungsten and their nitrides. typical see layer thicknesses are in the range of 1 microns to 10 microns.

The sputtering can be carried out, for example, with a plasma, wherein the temperature on the circuit board can remain below 150 degrees Cel ^¬ sius or even below 100 degrees Celsius. Particularly suitable for electroplating is copper, which is applied with a mask which covers areas of a base layer which are not to be electroplated for conducting electricity during electroplating.

For the assembly, the circuit board and the method, an extremely small structure for protecting an electrical circuit against external manipulation can be realized with standard electronic manufacturing processes. A high integration density ^¬ is made possible thereby. The circuit includes a control unit which, for example, result in the deletion of safety-relevant data, if an increase in the resistance of a conductor track structure ^¬ is detected.

Two cases can be distinguished. In the first case, the circuit board is on one side, for example on the front, be ^¬ fitted. In this case, in the production of printed circuit boards, a meander-shaped structure with the smallest possible structural spacing can be produced on the rear side, and through-connection to the front side is realized. A multilayer metal ^¬ capitalization with staggered meanders is possible to reduce the risk of external manipulation. After the assembly, a meander-shaped conductor track structure is produced on the front as follows. The circuit with a dielectric iso ^¬ lines. This may be a laminated film, a lacquer or a potting material. Depending on the surface topography, the dielectric may vary in thickness, for example in the range from 1 micrometer to several hundred micrometers.

Contacts to the backside contact and to the control structure are opened eg by means of laser ablation. The ensuing metalli ^¬ cal interconnect structure with contact to the backside metallization tion can be generated additive, semi-additive or subtractive. The surface of the dielectric is, for example, by means of gas phase senabscheidung, metallized, eg with Cu, and can ^¬ may be galvanically reinforced to several micrometers for Be. The metal layer is structured in a meandering pattern by means of photolithography and etching technology. The traces are so close together that they are damaged by drilling in the interstices and the total resistance increases.

To minimize the risk, a mehrla ^¬ giger structure can also be selected on the front side. In this case, the first interconnect ^¬ structure is covered with a dielectric. This may again be a laminated film, a lacquer or a potting material. Contact openings to the first metal level are opened again, eg by means of laser ablation. The surface is metalli ^¬ Siert, for example by vapor deposition, and the metal layer is added to the first metal plane meandering struc ^¬ riert. A final encapsulation for the mechanical and chemical protection of the overall structure is possible.

In the second case, the printed circuit board can be equipped on both sides. In this case, the metal patterning process is performed on both sides as described above.

The following technical effects are achieved:

- Electrical circuits can be safely protected in a compact design, which allows a high integration density ^¬

- the manufacturing process is possible with standard manufacturing ^{information model,}

the encapsulation additionally produces mechanical stability,

- The structure allows protection against optical inspection and chemical or mechanical manipulation.

In summary, the procedure is as follows: 1. Isolation of the circuit to be protected with a dielectric. Applying the dielectric, for example by means of Vergie ^¬ Shen, dipping or laminating a film. The film can also be photostructurable.

2. Opening of the contacts to the circuit and to the controller by means of photolithography and etching or by laser ablation. 3. metallization of the surface, e.g. by means of gas phase separation.

4. Optional: metallic reinforcement by electroplating for better mechanical stability.

5. Meandering structuring of the metal layer, for example by means of ^¬ photolithography and etching technique.

6. Optional: Potting for optical protection and / or protection against chemical or mechanical influences.

The monitoring circuit monitors for example. The ohmic resistance, the capacitance or the inductance of the conductor track ^¬ arrangement. In case of deviations from a desired value, an electrical signal is generated and optionally output, for example. Also, depending on the electrical signal, a deletion of data can be automatically initiated or even a destruction or change of components of the circuit, for example. With the help of so-called fuses or fuse fuses.

The energy for the monitoring circuit is stored, for example, in a storage capacitor, in a rechargeable battery or in a battery, which is located within the protective conductor track arrangement. Should the voltage in one of these energy stores fall below a predetermined value, then an automatic deletion can be initiated. In other embodiments, temperature and / or voltages are additionally monitored by the monitoring circuit. When the temperature rises or falls above or below a predetermined temperature value or the voltage above a predetermined voltage value, a deletion is likewise initiated.

The security-relevant data are, for example, encryption algorithms, electronic keys for electronic encryption and decryption methods, PIN codes (Personal Identification Number), important program data, important data records, etc.

At least two contacts of the circuitry may be routed outwardly through the protective track array as external terminals.

The circuit board is also referred to as a printed circuit and consists, for example, of FR4 (epoxy resin and glass fiber fabric) or FR5 material (epoxy resin and glass fiber fabric higher

Heat resistance) or from other materials such as phenol ^¬ resin, ceramic, etc.

The circuit board may be single or multi-layer apart from protection principles for monitoring and mostly with Kup ^¬ ferleitbahnen provided. Furthermore, the layers used for the circuit can be arranged only on one side of the circuit board or on both sides of the circuit board. Typical values for the layer thickness of the printed circuit board are in the range of 100 micrometers to 500 micrometers or even up to 2 millimeters.

The printed circuit board can be fixed or rigid and thus not bendable, or not below a bending radius of, for example, 10 centimeters. Alternatively, the printed circuit board can be flexible, ie bendable within certain limits of eg a radius of curvature smaller than 5 cm. The components are active components, such as Transisto ^¬ ren (BT (bipolar transistor), FET (Field Effect Transistor), diodes), or passive components, such as resistors, Kondensa ^¬ motors, coils, etc.

The components are usually soldered, for example in SMD technology (Surface Mounted Device) or provided with connection legs, which penetrate the holes in the circuit board. The above-described characteristics, features, and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments. Unless this application, the term "may" comparable uses is, it is both the technical Mög ^¬ friendliness and the actual technical implementation.

In the following, embodiments of the invention will be explained with reference to the accompanying drawings. Show:

Figure 1 is a plan view of a single-Schutzmetallisie ^¬ tion or protection interconnect arrangement,

2 shows a cross-section of the single-layer Schutzmetalli ^¬ tion with one-sided assembly,

3 shows a cross sectional view of another execution ^¬ example with two-sided mounting and einlagi ^¬ ger Schutzmetallisierung,

Figure 4 is a plan view of an embodiment with

multilayer protective metallization,

5 shows a cross section through the assembly with mehrla ^¬ giger protective metallization, FIG. 6 shows a first production stage in the production of a protected assembly, wherein an insulating layer has already been applied,

FIG. 7 shows a second production stage with Kontaktöffnun ^¬ conditions in the insulating layer,

FIG. 8 shows a third production stage with a first production stage

metallization

9 shows a fourth stage of manufacture with a galvanic ^¬ cally enhanced metallization,

FIG. 10 shows a fifth production stage with structured

Metallization layer, and

11 shows a sixth production stage with potting the

Assembly.

FIG. 1 shows a plan view of an assembly 10 which contains a single-layer protective metallization or protective conductor track arrangement 12.

Assembly 10 also includes:

- a circuit board 14, which can also be as a circuit carrier ^¬ records,

an electrically insulating insulating layer 16,

- Two contact portions 18 and 20, which penetrate the insulating layer 16 and are formed at the two ends of the conductor arrangement 12.

The conductor track arrangement 12 includes an axis extending in meandering conductor track which covers a part to be protected area of Lei ^¬ terplatte fourteenth Alternatively, the surface of the GESAM ^¬ th printed circuit board 14 is covered by the interconnect arrangement 12th In another embodiment, the Leiterbahnan ^¬ order 12, for example, a spiral shape. The circuit board 14 in the embodiment has a ^{rectangular ¬} plan. Alternatively, the circuit board 14 has a square plan or a different floor plan. The electrically insulating insulating layer 16 covers in the figure 1, not shown components of the assembly 10. The ^¬ se components form a useful circuit assembly 10 and ei ^¬ ne monitoring ^circuit . The useful circuit is for example:

a circuit for input and optionally display of a PIN,

a circuit containing a processor and an electronic memory with instructions and data for the processor, in particular an encryption circuit,

a transmission unit for a data transmission method, for example a radio transmission method, in particular for digital data, or

a receiving unit for a data transmission method, for example a radio transmission method, in particular for digital data.

In all cases, it is important to protect the circuit from unauthorized access, for example to prevent manipulation or to not disclose the structure of the circuit, for example software algorithms or hardware circuits.

The monitoring circuit contains, for example:

a resistance monitor whose inputs are connected to the track arrangement 14,

- A control circuit which generates an output signal when exceeding or falling below one or more setpoints, which is used, for example, for deleting data, for influencing the circuit or for delivering an electronic warning signal, and

- an optional energy storage.

The control circuit is constructed analog or digital, for example by means of a switching network or using a Surveillance processor or a processor used by the payload circuit. For the control circuit in particular mentioned in the introduction to the monitoring ^¬ circuit designs, eg ture additional temperatures and voltage monitoring apply.

Without energy storage in the assembly 10 Manipulatio ^¬ nen can be suppressed in the presence of an external voltage. Optionally, the deletion of the data can be carried out in the event of loss of voltage, for example, if the monitoring has not been properly disabled before.

With energy storage in the assembly 10, it is also possible to protect the circuit without concern an external voltage, for example. During transport or during a break in operation of a device.

FIG. 2 shows a cross section through the assembly 10, which contains the single-layer protective metallization or protective conductor track arrangement 12. The circuit board 12 is provided on its bottom side over the entire surface with a meander-shaped interconnect arrangement 50. Vias 52 and 54 penetrating the printed circuit board 12 connect the trace assembly 50 to the trace assembly 12, or alternatively directly to the monitoring circuitry 56, e.g. a controller based on, for example, microprocessor-based.

Components 58, 60 of a circuit 62 to be monitored are shown in the left part of FIG. The component 58 is, for example, a transistor or a diode. The component 60 is, for example, a resistor. Alternatively or additionally, the module 62 to be protected also contains an integrated circuit ^¬ circle. The monitoring circuit 56 may be arranged in another embodiment, which moreover resembles the embodiment shown ^¬ example, also below the protective conductor track assembly 12, which further the protection increases, ie the track assembly 12 then covers, for example, the entire circuit board 14th

A dummy device 64 is used for connecting the second end of the conductor track arrangement 56. 12 to the monitoring circuit instead of the dummy device 64 is used is a direct contacting of the Lei ^¬ terplatte 12 in an otherwise moving ^¬ chen embodiment. The monitoring circuit is then connected to the feedthrough 20 via a conductor track running on or in the printed circuit board 12.

FIG. 2 also shows a height H around which the highest component 64, 58, 60 of the assembly 10 protrudes beyond the printed circuit board 12. This height H is, for example, in the range of 50 micrometers to 500 micrometers. Alternatively, the height H may be larger or smaller.

A potting compound 66 contained in the assembly 10 additionally protects the assembly 10 from unauthorized intervention.

The protective trace assembly 50 is not connected to the guard trace assembly 12 in another embodiment, but is monitored by the monitoring circuitry 56 independently of the guard trace assembly 12.

FIG. 3 shows a cross-section through an assembly 100 with two-sided assembly of a printed circuit board 114 and a single-layer protective metallization or protective conductor arrangement 112.

Assembly 100 also includes:

an electrically insulating insulating layer 116 on the upper side,

two contact sections 118 and 120, which penetrate the insulating layer 116 and are formed at the two ends of the conductor track arrangement 112,

a monitoring circuit 156 which corresponds in terms of construction and function to the monitoring circuit 56, Components 158 and 160, which correspond to components 58 and 60 and which are part of a useful circuit 162,

an optional dummy device 164 that corresponds to the dummy device 64,

- One of the potting compound 66 corresponding potting compound 166th

A height Hl corresponds to the height H. On the underside of the printed circuit board 114 is at two-sided assembly now another useful circuit 101, which is covered by a further track arrangement 102 with a meandering course and thereby protected. Alternatively, the payload circuits 162 and 101 are also parts of a common payload circuit. The utility circuit 101 includes devices 104, 106 and an optional dummy device 108 that corresponds to the dummy device 164. A potting compound 110 additionally protects the assembly 100 against interference from below. FIG. 4 shows a plan view of an assembly 200 with multilayer protective metallization.

The assembly 200 includes:

a first protection trace arrangement 212 underlying a second protection trace arrangement 224,

an insulating layer 226 arranged between the two protective conductor tracks 212 and 222,

- a circuit board 214, which can also be as a circuit carrier ^¬ records,

an electrically insulating insulating layer 216, not shown in FIG. 4,

- two contact portions 218 and 220, which the insulating layer ^¬ penetrate and 216 are formed at the both ends of the lower protective-conductor track assembly 212, and

- Two contact portions 221 a and 221 b at the ends of obe ^¬ ren protective conductor arrangement 222nd The guard trace assemblies 212 and 222 are constructed like the guard trace assembly 12. The printed circuit board 214 is constructed like the printed circuit board 14. The insulating layers 216, 226 are constructed like the insulating layer 16. For the contact portions 218 and 220 that applies to the contact ^¬ portions 18, 20, said. The contact portions 221a and 221b serve to connect the upper protection trace array 222 to the monitor circuit of the assembly 200. The protection afforded by the assembly 200 shown in FIGS. 4 and 5 increases because at least two guard trace assemblies 212 and 222 are to be penetrated Intervened from above. The same applies to interventions from below, as will be explained in more detail with reference to FIG.

Accordingly, the assembly 200 includes a monitor circuit, not shown in Figure 4, the resistance changes, or change other characteristic electrical quantities of the protective-conductor arrangements detected 212 and 222 and causes the appropriate steps, if Ände ^¬ movements are recognized, for example. Deletion of relevant data.

FIG. 5 shows a cross section through the assembly 200 with multilayer protective metallization or protective conductor arrangements 212 and 222. According to FIG. 5, the assembly 200 furthermore contains:

- a monitoring circuit 256 which corresponds to the monitoring ^¬ circuit 56,

Components 258 and 260 which correspond to components 58 and 56 and which form part of a useful circuit 262,

an optional dummy device 264 that corresponds to the dummy device 64,

a potting compound 270, which provides additional protection against interference from above,

a first lower protection trace assembly 250, which is the

Protective conductor arrangement 50 corresponds and in particular ei ^¬ ne along a meander or a spiral (circular, square or rectangular) running track contains

a second lower protection trace arrangement 255 on the underside of the printed circuit board 214,

- Through holes 252 and 254, 52 and 54 corresponding to the Durchkon- clockings and connect the additional but also the second protective trace assembly 255 to the monitoring circuit 256. The contact portions 221a and 221b are not in the cross ^{¬ section} , which is shown in Figure 5, but are also connected via interconnects of the circuit board 214 with the monitoring ^¬ circuit 256. A lateral offset V between the guard traces 212 and 222 prevents gaps therebetween in which no guard traces are disposed when viewed from top of the package 200. There is also a lateral offset, not shown in FIG. 5, between the protective conductor track arrangements 250 and 255, which considerably complicates engagement from below.

The printed circuit boards 14 and 214 are also separately protected, that is, without assembly with components and without the upper protective trace assembly 12 and the protective trace assemblies 212 and 222 are available.

In another embodiment, separate through ^¬ contacts are also used for the connection of the protective conductor tracks 250 and 255. The guard trace assemblies 250 and 255 may also be monitored by the monitor circuit 256 independently of the guard trace assemblies 212 and 222. In other embodiments, both sides are populated and in each case two or more than two protective conductor arrangement are used above and below. Also in the case of the assembly shown in FIG. 5 or in the two-sided assembly mentioned in the previous paragraph, the monitoring circuit can be covered by the protective conductor track arrangements in order to increase safety. In the case of assembly on both sides, the monitoring circuit 156 can also be arranged on both sides of the printed circuit board 114.

6 shows a first manufacturing stage in the Her ^¬ position of protected module 10, in which has already been carried out as follows:

a printed circuit board manufacturer has produced the printed circuit board 14 according to customer requirements, with the protective printed conductor arrangement 50 and the plated-through holes 52 and 54 having already been produced by the conventional methods of printed circuit board technology, for example using photolithographic methods and etching processes,

the printed circuit board 14 was equipped with the components of the monitoring circuit 56 as well as with the components 58 and 60 of the useful circuit 62 as well as optionally with the optional dummy component 64,

- Subsequently, the insulating layer 16 was selectively applied ^¬ , for example. With a lift-off method. Alternatively, the insulating layer 16 is applied over the entire surface and patterned with a photolithographic process, for example. Together with the formation of holes for the contact portions 18 and 20th

The insulating layer 16 was, for example. USAGE laminated under ^¬ dung of pressure and temperature for example. In the range from 2 bar to 30 bar or in the range from 80 degrees Celsius to 190 degrees Cel ^¬ SIUS. As the material for the insulating layer, polyimide or epoxy is suitable. An optional additional adhesive layer or an adhesive film or a double-sided adhesive to set ^¬ foil facilitates the application. It is possible to use the foils customary in printed circuit board technology. The

Thickness of the film is, for example, in the range of 20 micrometers to 100 micrometers and in the range of 40 micrometers to 60 micrometers. Alternatively, the insulating layer 16 by casting, spin dryer or applied ^¬ dipping processes, forming no step at the edge of the insulating layer sixteenth Again, as a material for the insulating polyimide or epoxy geeig ^¬ net. The still viscous insulating layer is dried in air or by additional temperature processes, for example. At a temperature in the range of 80 degrees Celsius to 150 degrees Celsius.

7 shows a second manufacturing stage, have been introduced in the already be ^¬ contact openings 300, 302 and 304 in the insulating layer 16, for example. By laser pulses or by using a photolithographic method or wet etching process with subsequent closing drying. Alternatively, for the insulating layer 16 and a photosensitive film may be used, which is then selectively exposed and developed and remain of the areas as insulating layer 16 in the ^¬ group 10 ^¬ .

The contact hole 300 serves to accommodate the contact portion 18. ^¬ Accordingly, the contact hole is 304 for receiving the contact portion 20. The contact opening 302 receives a portion of the via 52.

FIG. 8 shows a third production stage with a first metallization layer 310 of the protective conductor arrangement 12. The metallization layer 310 is applied or sputtered from the gas phase (cathode sputtering) at temperatures at the insulating layer of, for example, only up to 80 degrees Celsius. The metallization layer 310 forms an adhesion-promoting layer and can serve as a base layer for the current supply in a galvanic process, possibly reinforced by a thin vapor-deposited or sputtered copper layer. As the material of the metallization layer 310 is approximately ^¬ eg. Suitable titanium, copper, tantalum, tungsten, chromium, a combination of these materials, or their nitrides. Also a multilayer structure of the metallic Sierungsschicht 310 is possible. The layer thickness of the metal ^¬ lisierungsschicht 310 is in the range of 5 micrometers to 15 micrometers. Typical values for a vapor deposition are 50 nanometers to 5 micrometers. The thicker the layer becomes, the more expensive it becomes. Theoretically, 15

Micrometer thick layers can also be achieved via the vapor deposition. If thicker layers (5 microns to 15 microns) are desired, the thin film process is typically combined with electrodeposition.

When the metallization layer 310 is applied, the contact sections 18 and 20 and an upper part of the through-connection 52 are formed. The through-connection 54 is also contacted by the first one at the edge of the insulating layer 16

Layer 310 for the production of the protective conductor arrangement 12.

FIG. 9 shows a fourth production stage with a galvanically produced metallization layer 320, which later forms the upper part of the protective conductor arrangement 12 and thus later amplifies the protective conductor arrangement 12, with regard to the mechanical stability. The metallization layer 320 is, for example, which is then patterned in a photolithographic process, a surface-wide applied Kup ^¬ ferschicht. Alternatively, a semiadditi ^¬ ves method is employed, in which a photomask is applied to the Me ^¬ tallisierungsschicht 310, after which the metallization layer 320 is already applied struc ^¬ riert out at ^¬ closing, for example. By electroplating.

The layer thickness of the metallization layer 320 is, for example, in the range of 20 micrometers to 50 micrometers. In addition to increasing the mechanical stability of the metallization layer approximately ^¬ 320 also leads to a significant reduction of the ohmic resistance of the Sands protection interconnect arrangement 12 which benefits the ease of detecting interruptions contrary. Further electrically conductive protective layers can be applied. Purification steps between the method ^¬ steps have not been described separately, in particular

Back sputtering steps to achieve clean surfaces.

10 shows a fifth stage of manufacture with struc tured ^¬ metallization layer 310, 320 whereby the protective conductor arrangement is generated 12th A photolithographic process using a photo-resist or a photo film, it is, for example, for structuring ^¬ tion. Employed. For struc ^¬ Center a wet chemical or dry chemical etching process is then used. The width of the conductor track or the conductor tracks of the protective conductor arrangement 12 is, for example, in the range of 50 micrometers to 100 micrometers, so that the patterning of copper is not a problem. In particular, the methods used from the production of printed circuit boards are known and optimized.

11 shows a sixth stage of manufacture with already applied sealing compound 66 of the assembly 10. The casting ^¬ mass 66 includes, for example, an epoxy. Black or dark ^¬ filling materials make it difficult to examine the optical assembly 10. When casting a wall can prevent lateral drift of the potting compound 66th Alternatively, a mold may be used in which the circuit board 14 is placed.

Instead of potting, a so-called mold process or injection molding process can be used in which the potting ^¬ mass is applied under pressure and temperature using a mold.

The assemblies 100 and 200 are produced analogously to the assembly 10, ie in particular using the erläu ^¬ terten methods, materials, layer thicknesses and manufacturing process.

In other embodiments, there are three protective conductor tracks or more than three protective tracks. arrangements, in particular with a meandering or spiral course arranged one above the other to further complicate manipulation. In further embodiments, the protective measures are combined with other protective measures.

The embodiments are not to scale and are not restrictive. Modifications in the context of expert action are possible. Although the invention in detail further illustrated by the preferred embodiment and has been be ^¬ enrolled, the invention is not limited by the disclosed examples and other variations Kgs ^¬ NEN be derived by those skilled thereof, without departing from the scope of the invention.

Claims

claims

1. Electronic assembly (10, 100, 200),

with a printed circuit board (14, 114, 214), on or in which at least two printed conductors or a plurality of printed conductors are arranged,

forming at least one electronic component (58) or ei ^¬ ner plurality of components (58, 60) or the one on the circuit board (14, 114, 214) arranged electronic circuit (62),

with a track arrangement (12) covering the circuit (62),

and with a monitoring circuit (56) whose inputs are electrically conductively connected to the track arrangement (12),

wherein an electrically insulating insulation layer (16) to Be ^¬ tenflächen of the component (58) or on side surfaces of the respective components (56, 58) is applied,

and wherein the track arrangement (12) is arranged on the insulating layer (16).

2. assembly (10, 100, 200) according to claim 1, wherein the Iso ^¬ lierschicht also on the printed circuit board (14, 114, 214) abge ^¬ facing side of the device (58) or on the components (58, 60). is arranged.

3. Assembly (10, 100, 200) according to claim 1 or 2, wherein the insulating layer (16) on the components (58, 60) so angeord ^¬ net is that on one of the components (58, 60) facing away from the insulating layer (16) height differences (H) greater than 50 microns or greater than 200 microns or greater than 400 microns occur,

wherein the conductor track arrangement (12) is arranged on the insulating layer, and wherein height differences greater than 50 micrometers or greater than 200 micrometers or greater than 400 micrometers occur on the track arrangement (12).

4. assembly (10, 100, 200) according to claim 3, wherein the Iso ^¬ lierschicht (16) is or contains a plastic film.

An assembly (10, 100, 200) according to claim 1 or 2, wherein the insulating layer (16) is a layer cast on the circuit board (14, 114, 214).

6. printed circuit board (14, 114, 214) with a conductor track layer (12) which contains in the area of the entire printed circuit board (14, 114, 214) or in an area to be protected at least one conductor track with a meandering or spiral course.

7. The printed circuit board (14, 114, 214) according to claim 6, wherein the conductor layer (250) is a first layer, and wherein the printed circuit board (214) includes a second printed conductor layer (255) which in the area of the entire printed circuit board (214 ) or in an area to be protected at least one further conductor track with mä ^¬ anderförmigem or spiral course contains.

8. printed circuit board (14, 114, 214) according to claim 7, wherein the

Conductor of the first conductor layer (250) is arranged with lateral offset to the conductor track of the second conductor layer (255).

9. A method for producing an assembly (10, 100, 200), wherein on a populated printed circuit board (14, 114, 214) a conductor track arrangement (12) is arranged separately without simultaneous placement of an insulating layer (16).

10. The method of claim 9, wherein on the circuit board

(14, 114, 214) at least one component (58) is arranged or a plurality of electronic components (58, 60) are arranged,

wherein an insulating layer (16) is applied to the component (58) or to the components (58, 60),

wherein an electrically conductive layer (310, 320) is applied to the insulating layer (16), and wherein the electrically conductive layer (310, 320) is structured after application to the insulating layer (16) to the conductor track arrangement (12).

11. The method of claim 10 wherein at least one conductor track of the conductor track arrangement (12) arranged with one on the printed circuit board (14, 114, 214) monitoring circuit (56) is connected to the assembly (10, 100, 200) against non ^¬ unauthorized Protects access.

12. The method according to claim 10 or 11, wherein the insulating layer (16) is applied as a film.

13. The method according to claim 12, wherein the film (16) is applied with overpressure or underpressure and / or with excess temperature.

14. The method of claim 10 or 11, wherein the insulating layer (16) is poured, spin coated or applied by dipping chen.

15. The method according to any one of claims 10 to 14, wherein the insulating layer (16) is geöff ^¬ net by means of laser in contact areas.

16. The method according to any one of claims 9 to 15, wherein the wiring arrangement (12) is applied by vapor deposition or sputtering, by electroplating or by both vapor deposition or sputtering and electroplating.