KR20140019320A - Device for testing electronic components having at least one embedded layer containing metal, method, and use of an electromagnetic acoustic transducer - Google Patents

Abstract

The present invention relates to an inspection device (10) for inspecting an electronic component (30), in particular a multilayer ceramic capacitor, comprising at least one embedded metal containing layer (32), said inspection device (10) having an electromagnetic acoustic transducer (12). Wherein the electromagnetic acoustic transducer generates an electromagnetic signal (RES) in response to an electromagnetic pulse (IMP) inside of the component (30) by generating one or more electromagnetic pulses (IMP) inside of the component (30) to be inspected. Includes a pulse generating unit 14 configured to generate a vibration causing the generation of a vibration signal, and includes a receiving unit 16 configured to receive an electromagnetic signal RES, and at least one signal RES at one or more time points. Analysis unit 18, which is configured to analyze the electromagnetic signal RES in relation to the amplitude or amplitude change of the < RTI ID = 0.0 > In addition, the inspection device 10 compares one or more threshold values TH with one or more amplitudes or amplitude changes of the signal, determined by the analysis unit 18, and according to this comparison, the parts to be inspected. 30 generates a first output signal SIG1 indicating that it is determined to function properly, or generates a second output signal SIG2 indicating that the component 30 to be inspected is determined to be defective. Also included is an evaluation unit 20. In addition, the present invention also relates to a corresponding method and to the use of the electromagnetic acoustic transducer 12.

Description

DEVICE FOR TESTING ELECTRONIC COMPONENTS HAVING AT LEAST ONE EMBEDDED LAYER CONTAINING METAL, METHOD, AND USE OF AN ELECTROMAGNETIC ACOUSTIC TRANSDUCER}

The present invention relates to an inspection apparatus for inspecting electronic components, in particular multilayer ceramic capacitors, comprising one or more embedded metal containing layers.

The invention also relates to a corresponding method and to the use of an electromagnetic acoustic transducer.

Inspection of the electronic components is very important because there is a significant additional cost in the production process if the electronic components are detected due to a malfunction of the first relatively larger assembly. Therefore, the buyer side of today's electronic components requires that each component be inspected for possible defects before the components are usually supplied to the production process.

Ultrasonics is the most widely used technology for inspecting electronic components. For the inspection, the part is connected to an ultrasonic transducer and then supplied with ultrasound. The mechanical structure of the part reflects the ultrasonic waves, and the ultrasonic echo generated in the component is received by the ultrasonic transducer. Depending on the echo, it can be determined whether the part functions properly or whether the part is defective.

Although the inspection principle with ultrasound may seem simple, the practical implementation is relatively expensive. Ultrasonics, on the other hand, demands that the parts are very reliably connected to the ultrasonic transducers. In addition, the connection must be uniform throughout the part, otherwise the measurement results are distorted. Finally, the part must be positioned very accurately with respect to the ultrasonic transducer since very different echoes can occur even if there is already a slight deviation from the set position.

This actually means that only a few parts per minute can be inspected by ultrasound. In this case, given the fact that you have to actually produce hundreds or even thousands of parts per minute, it is clear that only a small percentage of the parts can actually be inspected.

It is an object of the present invention to present an improved inspection apparatus, corresponding method, and the use of electromagnetic acoustic transducers for inspecting electronic components in order to enable effective inspection of the electronic components.

The problem is an inspection device for inspecting an electronic component, in particular a multilayer ceramic capacitor, comprising at least one embedded metal containing layer, said inspection device comprising an electromagnetic acoustic transducer, said electromagnetic acoustic transducer being the interior of the component to be inspected. A pulse generating unit configured to generate a vibration in the interior of the component to generate an electromagnetic signal for the electromagnetic pulse by generating at least one electromagnetic pulse, wherein the receiving unit is configured to receive the electromagnetic signal, An analysis unit configured to analyze the electromagnetic signal in relation to at least the amplitude of the signal at one or more time points; in addition, the inspection device further comprises one or more thresholds TH and one or more amplitudes of the signal determined by the analysis unit. Comparable and parts to be inspected according to this comparison And an evaluation unit for generating a first output signal indicating that the component to be inspected is determined to be defective, or for generating a second output signal indicating that the component to be inspected is defective.

First of all, before describing the features of the present invention and the estimated technical basis, reference should be made here to the description of the multilayer ceramic capacitor, although this is in no way applicable to the multilayer ceramic capacitor. It does not represent a limit to the extent possible. Rather, in connection with the following description, it is intended that the present invention be generally used in parts comprising one or more embedded metal containing layers. Indeed, since particularly convincing and statementable test results are achieved here, a preferred example of a multilayer ceramic capacitor will now be discussed.

Multilayer monolithic capacitors are used in various fields in the electrical industry. The capacitor, in particular the ceramic capacitor, consists of a ceramic block in which a plurality of metal containing layers, in particular a metal layer, is arranged. The layers are also referred to as electrodes in the case of a capacitor.

In order to ensure that the ceramic capacitors continue to function properly and maintain the desired specifications, the bonding or adhesion between the layers and the ceramic body must be good. If not, the electrical characteristics of the capacitor may change. In addition, the capacitors may show a fault immediately or in time. Among the known defects that may result in this result are the separation of the hollows inside the ceramic body and one or more layers from the ceramic body.

An electronic component comprising at least one embedded metal containing layer, here an inspection device according to the invention for inspecting a ceramic capacitor, comprises a pulse generating unit capable of generating one or more electromagnetic pulses inside the ceramic capacitor. The electromagnetic pulse exerts a force on the layers inside the capacitor via the pulse, even if it has only little or no effect on the carrier material, here ceramic, in which the layers are embedded.

According to the point of view in the scope of the present invention, since the layers are embedded in the ceramic, the force acting on the layers is also transferred to the ceramic, ie to the material in which the layers are embedded internally. This in turn allows the vibrations to be excited inside the part, in particular the resonance vibrations of the areas of the part connected with the layers or the resonance vibrations of the part as a whole.

Since the metal containing layers, in particular the metal layers, are embedded in the vibrating carrier material, the layers are subjected to the same resonance vibration as the entire area or the aforementioned areas of the part. The vibration of the layers then generates an electromagnetic signal in response to the electromagnetic pulse. The electromagnetic pulse may be received by the receiving unit of the electromagnetic acoustic transducer.

In addition, according to what has been identified in the scope of the present invention, the electromagnetic response signal of a properly functioning part is distinguished from the response signal of a defective part to a discernible degree. This is particularly evident in the case of the ceramic capacitors described. If the layers are not sufficiently bonded with the carrier material, here ceramic, then the force generated by the electromagnetic pulse is only insufficiently transferred onto the carrier material. In addition, less vibration of the carrier material is inadequately transferred back onto the layers, so that vibrations of the layers of the defective part appear much smaller than in a properly functioning part.

Therefore, the amplitude of the electromagnetic response signal is then analyzed in the analysis unit. This can be done in a variety of ways. Preferably, the amplitude of the response signal is analyzed immediately when the response signal reaches the receiving unit. In addition, it is advantageously possible to first wait until the vibration of the response signal is at least two times, preferably at least five times, particularly preferably at least ten times, and then analyze the amplitude of the response signal. In this case, the amplitude of the response signal can be averaged over particularly preferably two or more times, preferably five or more times, and particularly preferably ten or more times. Finally, for the analysis of the amplitude, it can be determined, preferably, at which time range a preset relative or absolute decrease in amplitude has been initiated.

As already explained, according to what has been confirmed by practical experiments, the multilayer ceramic capacitors are particularly reliably separated into defective parts and parts that function properly by the idea according to the invention. Therefore, the foregoing description and the following description focus on the capacitor.

However, in the context of the presumed technical background, it is apparent that the present invention is generally suitable for inspecting electronic components comprising one or more embedded metal containing layers. In other words, for each part, each part can be applied by an electromagnetic pulse to which a force can be applied to the embedded layer of the part, the layer of the part transmitting force onto the carrier material in which the layer is embedded internally. It can be examined by the idea according to the invention.

Although the electromagnetic signals in the various parts are distinguished from one another in relation to, for example, the shape of the signal, the absolute magnitude of the amplitude, or the relative difference between the amplitude in the suitably functioning part and the amplitude in the defective part, these types of parts Depending on whether they function properly or are each defective, they respond with response signals that can be distinguished in terms of the amplitude of the components themselves.

In a particularly simple preferred embodiment of the invention, the threshold value is used as a limit value on whether the part functions properly or is judged to be defective. In short, when the threshold is reached or the threshold is exceeded, a first output signal is generated that indicates the component functioning properly. If the threshold is lower, a second output signal is generated indicating the defective part.

In the case of a preferred refinement of the approach, in addition to the first threshold described above, a second threshold may also be used. In this case, the following logic is preferable. In short, if the first threshold is reached or exceeded, the first output signal is generated. If the second threshold is reached or below the second threshold, a second output signal is generated. If the first threshold is lowered and the second threshold is exceeded, a third output signal is generated indicating that the part was not identified as defective or functioning with sufficient reliability.

With regard to the first and second output signals, reference is to be made to the signals as long as they can be distinguished from each other. On the contrary, it is not necessarily necessary to be able to distinguish the two output signals from further states, in particular stationary states. If, for example, it is determined that the digital HIGH signal indicates a component functioning properly as the first output signal, not only the LOW signal but also simply the absence of the HIGH signal can be considered as the second output signal. Also in a corresponding manner, the second output signal may be determined as the digital HIGH signal and the absence of the HIGH signal may be determined as the first output signal.

The analysis unit and the evaluation unit are preferably integrated in particular in a microprocessor (μC) or a programmable logic device (PLD). In addition, the pulse generating unit and the receiving unit are preferably realized by an assembly, whereby the same assembly is responsible for the generation of electromagnetic pulses as well as for the reception of electromagnetic signals. Besides, preferably, the pulse generating unit and the receiving unit may be formed independently of each other.

Noted explicitly here is the preferred use of the present invention. In short, the inspection of electronic components can be carried out in a dry environment, that is, there is no need to put the components in liquid to form a connection between the test head, in particular the ultrasonic test head and the component. This greatly simplifies the inspection. In particular, no connection medium is required to enable signal transmission between the test head and the component at low attenuation conditions. In this case, air, which is always present everywhere, is not considered as a connecting medium.

Finally, it is noted that the principle of the electromagnetic acoustic transducer is assumed to be known and is not described in more detail in the scope of the present application. Therefore, the patent US 4,777,824, US 5,811,682, US 6,282,964, US 7,546,770 are referred to by way of example only as a citation for notifying the principle of the above technique.

Therefore, the subject of this application is solved completely.

In a preferred embodiment of the invention, the evaluation unit is configured to receive one or more first numerical input values and to determine a threshold TH based on the input values.

This embodiment is preferred because the inspection apparatus of the present application can be adapted to suit the desired part type to be inspected in a simple manner as a result, and / or the switching between the various part types can be made quickly. In the simplest case, preferably a numerical value for the amplitude representing the threshold TH is received. In a further case, preferably, the numerical input value describes the part type to be inspected, and under conditions of which the part type is known, the preset threshold is determined in particular according to a diagram stored in a memory element in the inspection apparatus of the present application. . The values of the plot, so-called reference values, can be determined according to the experiment in advance.

In a further preferred embodiment of the invention, the evaluation unit is configured to determine the threshold TH from the pilot amplitude AMP _PILOT determined by the analysis unit in the first mode of operation.

This embodiment has the advantage that it is possible to inspect various part types, but not to determine reference values in advance for the individual part types. In the case of this embodiment, the inspection device of the present application is first switched to the first mode of operation. This is preferably done via a switch or through the reception of a corresponding control signal.

Then, as is known, defective parts are inspected as appropriate. The amplitude determined here is referred to as the pilot amplitude AMP _PILOT . The threshold is then determined based on the pilot amplitude. In short, as will be appreciated, if a properly functioning part is used, the threshold is preferably chosen to be smaller than the pilot amplitude. As noted, if a defective part is used, the threshold is preferably chosen to be larger than the pilot amplitude.

In this regard, depending on what is considered to be an advantage, a plurality of pilot amplitudes are determined, whether based on a single component or a group of defective components, as appropriately known or functionally known. Is determined based on the average of the pilot amplitudes.

In a further preferred embodiment of the invention, the evaluation unit is configured to calculate the threshold TH as TH = AMP _PILOT * F, wherein F is between 0.01 and 0.9, preferably between 0.05 and 0.75, particularly preferred. Preferably between 0.1 and 0.6, in particular between 0.15 and 0.5.

This embodiment is preferred because, as a result, a suitable threshold is indeed reliably determined according to a few parts, in particular one part, in a simple manner. The numerical values of the factors are based on the assumption that a suitably functioning part is used for the determination of the pilot amplitude. As is known, if a defective part is used, the factor is chosen between 1.1 and 100, preferably between 1.3 and 20, particularly preferably between 1.6 and 10, in particular between 2 and 7.

In a further preferred embodiment of the invention, the evaluation unit, in the first mode of operation, checks for defective parts as well as for the first pilot amplitude determined by the analysis unit in the inspection of the parts functioning as well known. And determine a threshold value from the second pilot amplitude determined by the time analysis unit.

In the case of the above embodiment, the advantage is provided that the threshold value can be determined particularly reliably under conditions of knowledge of the first pilot amplitude of the component functioning properly and the second pilot amplitude of the defective component. For a simple embodiment, the threshold is preferably determined as the average of the first pilot amplitude and the second pilot amplitude, more precisely under conditions that take into account a logarithmatic scale.

In a further preferred embodiment of the invention, the analysis unit is configured to analyze the amplitude at least near the resonant frequency.

The above embodiment is preferable because the analysis of amplitude is not made in a wide band, and therefore the incidental effects or interferences that occur in the case may only have a slight or no action on the measurement of the amplitude. Determination of the resonant frequency can be carried out for each component individually, in particular with the frequency spectrum of the electromagnetic response signal being analyzed at intervals.

Further, preferably, the resonant frequency for the part type is previously determined experimentally and then assumed to be constant for all parts of the part type. This achieves particularly high throughput during inspection.

In a further preferred embodiment of the invention, the analysis unit receives a second numerical input value that determines one or more of the values consisting of a group of variables n, c and h, and f _n = nc / 2h Or f _n = nc / 4h, where n is a natural number, c is the speed of sound inside the part, and h is the length of the part that is the path through which vibrations within the part are initiated.

This embodiment is preferred because, as a result, the resonant frequency of the part can be estimated in a simple manner and / or a certain starting value for the search for the resonant frequency can be determined. It should be noted that, in the following, consideration is made on the basis of consideration of the occurrence of resonance according to a substantially monolithic component, especially a multilayer ceramic capacitor.

Considering the part along the length h of the part, that is to say along the length that is the path from which vibrations in the part begin, the resonance situation for the longitudinal wave occurs when h = nλ / 2. In addition, λ = c / f _n is applied. The formula f _n = nc / 2h is then obtained from this, preferably the first resonant frequency f ₁ = c / 2h. Assuming that the sound velocity inside the ceramic body is 5000 m / s and the associated length h is 2 mm, f ₁ ? 1.25 MHz is obtained.

Resonance is also achieved by a transverse wave having a frequency approximately equal to half of the longitudinal wave. Then, the formula f _n = nc / 2h / 2 = nc / 4h is obtained from this. Regarding the example just mentioned, f ₁ ? 0.62 MHz.

Basically if the first resonant frequency is used, then n = 1 is applied, not the input of n. Also, if checking for various component types, which can usually give the same sound velocity, the input of c is not required. In this case, rather, the speed of sound can be preset as a constant value. If the associated length h remains constant across the various part types, then no input of h is required.

In a further preferred embodiment of the invention, the analysis unit is configured to, in the third mode of operation, analyze the amplitudes at frequency intervals by the frequency start value and determine the frequency with the maximum amplitude as the resonant frequency of the part.

This embodiment is preferred because, as a result, the resonance frequency is determined at least approximately in a simple manner. Basically, the frequency starting value can be chosen almost arbitrarily, as long as the value of the frequency interval can ensure that the resonant frequency is located within the frequency interval. If the frequency starting value is preferably determined according to the above-described formulas f _n = nc / 2h or f _n = nc / 4h, the frequency interval can be chosen with a relatively narrow width, since the formula is substantially at resonance frequency. This is because it shows a suitable approximation.

In a further preferred embodiment of the invention, the electromagnetic acoustic transducer comprises an active surface for emitting electromagnetic pulses and / or for receiving sound waves, in addition the inspection apparatus of the present application automates the part to be inspected. It also includes a feeding device which guides in a manner at least near the active surface, in particular in contact with the active surface.

This embodiment provides the advantage that the inspection can be carried out in an automated manner. In this case, the part to be inspected by the feeding device is first moved near the active surface. The part is then inspected in the manner described above. After the end of the inspection, the supply device then removes the inspected part and moves the subsequent part to be inspected near the active surface. Then, in a further inspection process, the inspection continues continuously.

In this regard, reference is that the electromagnetic acoustic transducer may comprise a plurality of active surfaces, or may comprise a plurality of areas in which the active surfaces can be controlled separately. In this case, in the case of the inspection apparatus, a plurality of parts can be inspected at the same time. In addition, reference is made to the concept of "near the active surface" preferably meaning an interval of less than 2 cm, preferably less than 5 mm, particularly preferably less than 2 mm, in particular less than 1 mm. .

In a further preferred embodiment of the invention, the feeding device is configured to guide a plurality of parts to be inspected arranged on the carrier material in series, at least near the active surface, in particular in contact with the active surface.

This embodiment offers a particularly sure and rapid possibility of guiding the parts to be inspected near the active surface in an automated manner.

In a further preferred embodiment of the invention, the pulse has a length of less than 10 ms, preferably less than 2 ms, particularly preferably less than 1 ms, in particular less than 500 ms.

This embodiment provides the advantage that a broad spectrum of frequencies can be excited within the part. This ensures that the part is excited at its own resonant frequency, particularly with certainty.

In a further preferred embodiment of the invention, the component is a multilayer capacitor, in particular a multilayer ceramic capacitor.

The inspection apparatus of the present application is particularly preferably used in the inspection of multilayer capacitors. Specifically within the scope of the present invention, it has been found that, according to practical experiments, clear differences in the electromagnetic response signal are indicated depending on whether the capacitors, in particular multilayer ceramic capacitors, function properly or are defective. .

The problem of the present application is also solved through a system for inspecting electronic components using the inspection apparatus described above and one or more electronic components to be inspected, wherein the components are in particular multilayer capacitors, particularly preferably multilayer ceramic capacitors.

The subject matter is also solved through an inspection method for inspecting electronic components, in particular multilayer ceramic capacitors, comprising one or more embedded metal containing layers, the inspection method comprising the following steps.

Receiving an electromagnetic signal,

Analyzing the electromagnetic signal with respect to at least the amplitude of the signal at one or more time points,

Comparing the determined amplitude of the electromagnetic signal with one or more thresholds, and

Generating a first output signal indicating that the part to be inspected is judged to be functioning properly, or generating a second output signal indicating that the part to be inspected is determined to be defective.

In a further preferred embodiment of the invention, the inspection method herein further comprises the following steps.

Determining a pilot amplitude when inspecting a well-functioning component or a defective component as is well known, and

Determining a threshold value based on the determined pilot amplitude.

Finally, the subject matter is also solved through the use of electromagnetic acoustic transducers for inspecting electronic components, in particular multilayer ceramic capacitors, comprising one or more embedded metal containing layers.

Obviously, the features mentioned above and described again below can be used not only in the specified combinations, but also in other combinations, or independently, without departing from the scope of the invention.

In addition, it is also obvious to note that each embodiment of the analysis unit and the evaluation unit also discloses corresponding processing steps that can be executed by a processor or programmable logic element as a single instruction or small program.

Also disclosed and claimed are corresponding uses of the inspection apparatus of the present disclosure for inspecting electronic components, each of which includes one or more embedded metal containing layers, for all embodiments of the inspection apparatus of the present disclosure. This applies especially to the use for inspecting multilayer ceramic capacitors.

In conclusion, it is to be noted that, in connection with the present invention and preferred embodiments of the present invention, at least the following aspects are each considered to be new aspects, alone, but in particular in combination with one or more aspects.

For the inspection of parts, especially capacitors, the mechanical resonance frequencies of the parts are used. The mechanical resonance frequency is in particular mechanical free vibration.

To vibrate the part, metal-containing constituent members and / or metal constituent members of the part, in particular metal layers of the capacitor, are used.

In order to excite the mechanical vibrations of the metal component parts of the part, magnetic fields and electromagnetic waves are preferably supplied to the part under the conditions in which magnets or electromagnets are used.

In order to transmit the mechanical vibration of the metal component parts on the body of the part, the point of joining the metal component parts of the part to the body of the part is used.

Based on the coupling, the vibration of the body of the part acts again on the metal component parts.

The movement of the metal components within the magnetic field described above generates an electromagnetic signal as a response.

An electromagnetic acoustic transducer is used to excite the free vibration of the part and receive a response. In this case, a first transducer for exciting the vibrations and a second transducer for receiving the response may also be used. The magnetic field can also be generated with additional magnets.

Embodiments of the invention are shown in more detail in the drawings and are described in more detail in the following description.
1 illustrates an inspection apparatus for inspecting electronic components including one or more embedded metal containing layers.
2 shows a capacitor including a plurality of metal layers embedded in a carrier material.
3 is a graph showing the electromagnetic response signal of a properly functioning capacitor.
4 is a graph showing the electromagnetic response signal of a properly functioning capacitor.
FIG. 5 is a flow diagram illustrating an inspection method for inspecting electronic components comprising one or more embedded metal containing layers, here capacitors each comprising a plurality of metal layers embedded in a carrier material.

1 shows an inspection device 10 for inspecting electronic components 30 (see FIG. 2), in particular multilayer ceramic capacitors, comprising one or more embedded metal containing layers 32.

The inspection device 10 includes an electromagnetic acoustic transducer 12, which generates one or more electromagnetic pulses IMP within the component 30 to be inspected, thereby generating an electromagnetic pulse (I) inside the component 30. And a pulse generating unit 14 formed to cause vibrations of the layers 32 generating the electromagnetic signal RES in response to the IMP. The inspection device 10 and the component 30 form one system 11.

In addition, the inspection apparatus 10 includes a receiving unit 16 configured to receive an electromagnetic signal RES. Although the pulse generating unit 14 and the receiving unit 16 are formed separately from each other according to a further not shown embodiment, in this embodiment the pulse generating unit 14 and the receiving unit 16 are realized as an assembly. The situation is shown. This realization is known in electromagnetic acoustic transducers.

In addition, the inspection device 10 includes an analysis unit 18, which is configured to analyze the electromagnetic signal RES at least one time point in relation to an amplitude or amplitude change of the signal RES.

Finally, the inspection apparatus 10 comprises an evaluation unit 20, which is one or more thresholds TH and one or more amplitudes or amplitude changes of the signal RES determined by the analysis unit 18. And generate a first output signal SIG1 indicating that the component 30 to be inspected is functioning properly according to the comparison, and / or determine that the component 30 to be inspected is defective. It is configured to generate a second output signal SIG2 indicating that it is.

As already described, one output signal of the output signals SIG1 and SIG2 may be simply formed as an absence of the signal. In the case of a suitably functioning component 30, if the signal SIG1 is confirmed to be transmitted, the absence of the signal SIG1 can be interpreted as the second output signal SIG2, whereby the defective component can be inferred. Can be. The output signals SIG1, SIG2 should be distinguishable from each other, but need not be explicitly determined.

The electromagnetic acoustic transducer 12 includes an active surface 22 for emitting an electromagnetic pulse IMP and receiving an electromagnetic signal RES. In addition, the inspection device 10 comprises a supply device 24 which guides the parts 30 to be inspected in an automated manner at least near the active surface 22, in particular in contact with the active surface 22. The supply device 24 is specifically designed to guide the plurality of parts to be inspected 22 disposed on the carrier material 26 in succession at least near the active surface 24, in particular in contact with the active surface 24. do.

2 shows a component 30 formed here as a multilayer ceramic capacitor. Metal layers 32 of the ceramic capacitor are embedded in the carrier material 34, here in the ceramic body. The layers 32 are here alternately connected with the first bonding area 36 and the second bonding area 38. In addition, a defect 40 is shown inside the component 30, where the coupling of one or more layers 32 to the carrier material 34 is omitted. Finally, the relative length h is also shown when the vibration of the part 30 is assumed to be in a direction approximately perpendicular to the surface of the layers 32.

Here, as already explained, it is based on the fact that the layers 32 are energized via an electromagnetic pulse IMP, and the force also acts on the carrier material 34. Then, after the end of the pulse IMP, the carrier material 34 comprising the layers 32 returns to a stationary state as the vibration decreases. The movement of the layers 32 inside the magnetic field generated by the electromagnetic acoustic transducer produces an electromagnetic response signal RES received by the receiving unit 16.

3 shows an example of a functioning component 30, here an electromagnetic response signal RES generated from a multilayer ceramic capacitor. The time is displayed along the abscissa and the signal strength of each of the electromagnetic signals RES is shown along the ordinate. The amplitude of the electromagnetic signal RES is analyzed here in terms of its maximum value. The maximum value of amplitude in the suitably functioning component 30 is referred to as AMP _FKT .

In addition, the figure shows the selected threshold value TH for the multilayer ceramic capacitor of the component type. Obviously, the amplitude (AMPFKT) clearly exceeds the threshold (TH). Thus, component 30 may be determined to function properly.

4 shows by way of example an electromagnetic response signal RES produced by a defective component 30, here the multilayer ceramic capacitor shown in FIG. 2. The time is also displayed here along the abscissa and along the ordinate the respective signal strengths of the electromagnetic signal RES. The amplitude of the electromagnetic signal RES is analyzed in terms of its maximum as before. The maximum value of amplitude in the defective part 30 is referred to as AMP _DEF .

Unlike FIG. 3, it is confirmed here that the threshold TH is clearly lower. Therefore, the component 30 can be judged as defective.

In FIG. 5, one embodiment of an inspection method for inspecting electronic components including one or more embedded metal containing layers is shown. The inspection method starts with step S1.

In step S2, as is well known, the component 30 functioning appropriately is used, and the pilot amplitude AMP _PILOT is determined upon inspection of the component. Then, a threshold (TH) from the pilot amplitude (AMP _PILOT), in step S3, for example as TH = 0.5 * AMP _PILOT is computed. Then, in step S4, the first electronic component 30 to be inspected is moved to the inspection position in front of the inspection apparatus 10 of the present application.

In step S5, one or more electromagnetic pulses IMP are transmitted from the pulse generating unit 14 to the component 30 to be inspected, whereby a vibration occurs inside the component 30, which vibration is generated by the electromagnetic pulse IMP. Generates an electromagnetic signal (RES) as a response. The electromagnetic signal RES is received by the receiving unit 16 in step S6.

The electromagnetic signal RES is analyzed in relation to at least one amplitude or amplitude change of the signal RES at one or more time points in step S7. In this case, the analysis is preferably at least near the resonant frequency of the component 30. In the case of the ceramic capacitor described above, the resonance frequency is in particular the resonance frequency at which the layers 32 vibrate approximately perpendicular to the surface of the layers 32 together with the carrier material.

In step S8, the determined amplitude AMP of the electromagnetic signal is compared with one or more thresholds TH. If the threshold is exceeded, the inspection method herein branches to step S9 via branch J, where a first output signal is generated indicating that the component 30 to be inspected is determined to be functioning properly at step S9. If the threshold is not exceeded, the inspection method of the present application branches to step S10 via branch N, in which a second output signal is generated indicating that the component 30 to be inspected is determined to be defective.

In step S11, it is checked whether the final part has been inspected. If the final part has not been inspected, the inspection method of the present application branches to step S12 via branch N, where the electronic component 30 to be inspected subsequent to this step S12 is the inspection position in front of the inspection device 10 of the present application. Is moved to. If the final part has been inspected, the inspection method of the present application ends with step S13 through branch J.

In total, an apparatus, method and use for inspecting electronic components, in particular multilayer ceramic capacitors, including one or more embedded metal containing layers, said apparatus capable of enabling a significantly increased inspection speed of up to a plurality of components per second. , Methods and uses were specified.

Claims (15)

An inspection device 10 for inspecting electronic components 30, in particular multilayer ceramic capacitors, comprising one or more embedded metal containing layers 32, said inspection device 10 comprising an electromagnetic acoustic transducer 12 and The electromagnetic acoustic transducer generates an electromagnetic signal RES in response to an electromagnetic pulse IMP within the component 30 by generating one or more electromagnetic pulses IMP within the component 30 to be inspected. A pulse generating unit 14 configured to cause vibration to be generated; a receiving unit 16 configured to receive an electromagnetic signal RES, and at least one amplitude or amplitude of the signal RES at one or more time points. In the inspection apparatus 10, comprising an analysis unit 18 configured to analyze the electromagnetic signal RES in connection with a change,
In addition, the inspection apparatus 10 also includes an evaluation unit 20, which includes one or more threshold values TH and one or more amplitudes of the signal RES determined by the analysis unit 18, or Compare the amplitude change and generate a first output signal SIG1 indicating that the component to be inspected is judged to function properly according to the comparison, or the component 30 to be inspected is defective And generate a second output signal (SIG2) indicating that it is determined to be. The inspection apparatus according to claim 1, wherein the evaluation unit (20) is configured to receive one or more first numerical input values and to determine a threshold (TH) based on the input values. The inspection apparatus according to claim 1, wherein the evaluation unit (20) is configured to determine a threshold value (TH) from a pilot amplitude (AMP _PILOT ) determined from the analysis unit (18) in a first mode of operation. 4. The evaluation unit (20) according to claim 3, wherein the evaluation unit (20) is configured to calculate the threshold (TH) as TH = AMP _PILOT * F, wherein F is between 0.01 and 0.9, preferably between 0.05 and 0.75, in particular Preferably a factor between 0.1 and 0.6, in particular between 0.15 and 0.5. 2. The evaluation unit 20 according to claim 1, wherein the evaluation unit 20, in the first mode of operation, has a first pilot amplitude determined by the analysis unit 18 in the inspection of the part 30 functioning as known. The inspection apparatus, as described above, is configured to determine a threshold value (TH) from the second pilot amplitude determined by the analysis unit (18) upon inspection of the defective component (30). The inspection apparatus according to any one of claims 1 to 5, wherein the analysis unit (18) is configured to analyze an amplitude at least in the vicinity of a resonance frequency of the component (30). 7. The analysis unit (18) according to any one of the preceding claims, wherein the analysis unit (18) receives a second numerical input value that determines one or more of the values consisting of a group of variables (n, c and h). And calculate a resonant frequency as f _n = nc / 2h or f _n = nc / 4h, where n is a natural number, c is the speed of sound inside the component 30, and h is in the component 30. Inspection device, which is the length of the component (30) that is the path from which vibration is initiated. 8. The analysis unit (18) according to any one of the preceding claims, wherein the analysis unit (18) analyzes the amplitudes at frequency intervals by the frequency start value in the third mode of operation and maximum amplitude as the resonance frequency of the component (30). And to determine a frequency having an angle. The active surface 22 as claimed in claim 1, wherein the electromagnetic acoustic transducer 12 emits the electromagnetic pulse IMP and / or receives the electromagnetic signal RES. In addition, the inspection device 10 furthermore provides a supply device 24 for contacting the active surface 22, in particular with the active surface 22, which guides the component 30 to be inspected at least near the active surface 22 in an automated manner. Inspection apparatus, including). 10. The apparatus according to claim 9, wherein the supply device 24 is adapted to guide the plurality of parts to be inspected 30 arranged on the carrier material 26 in succession at least near the active surface 22, in particular the active surface ( 22. An inspection device, configured to be in contact with 22). The inspection device according to claim 1, wherein the pulse IMP has a length of less than 10 ms, preferably less than 2 ms, particularly preferably 1 ms, especially less than 500 ms. . 12. A system (11) comprising an inspection device according to any one of the preceding claims and at least one electronic component (30) to be inspected, wherein the component (30) is in particular a multilayer capacitor. An inspection method for inspecting electronic components 30, in particular multilayer ceramic capacitors, comprising one or more embedded metal containing layers 32,
Transmitting at least one electromagnetic pulse IMP to the electronic component 30 to be inspected such that a vibration is generated inside the component 30 which generates an electromagnetic signal RES in response to the electromagnetic pulse IMP. Step S5,
Receiving the electromagnetic signal RES (S6),
Analyzing the electromagnetic signal RES in relation to at least one amplitude or amplitude change of the signal RES at one or more time points S7;
Comparing (S8) at least one threshold value (TH) with a determined amplitude of the electromagnetic signal (RES),
Generating a first output signal SIG1 indicating that the component to be inspected 30 is determined to function properly (S9), or indicating that the component to be inspected 30 is determined to be defective; Generating the second output signal (S10). The method of claim 13, wherein
Determining a pilot amplitude AMP _PILOT when inspecting a well-functioning part or a defective part 30 as is well known (S2),
Determining a threshold value TH based on the determined pilot amplitude AMP _PILOT . Use of an electromagnetic acoustic transducer 12 for inspecting electronic components 30, in particular multilayer ceramic capacitors, comprising one or more embedded metal containing layers 32.

Images