HK1112290A - Method and system for testing or measuring electrical elements - Google Patents

Abstract

The invention concerns a method for testing or measuring electrical elements, wherein a beam (6) of particles is applied to a location of an electrical element (2, 3), charges are released under the effect of the application of the beam (6) of particles, the released charges are collected by a collector (9), the amount of collected charges is measured, and an electrical characteristic is derived from the measurement of the amount of charges collected. The invention is applicable, in particular, to measuring the resistance and/or the capacity of printed circuits, as well as to any other type of substrates such flat displays, circuits equipped with components, semi-conductor chips.

Description

Method and system for testing or measuring electrical components

Technical Field

The present invention relates to a method for testing or measuring electrical components, and to a corresponding system.

Background

Electrical components, such as semiconductor or integrated circuit chips, and printed circuits, are subjected to various testing steps that are an integral part of their fabrication process prior to being marketed. Among the tests performed, some determine the continuity and insulation of the conductor paths. Other tests may evaluate the resistance of each conductor path.

The document US-6,369,591B 1(Cugini et al) describes a contactless method for testing the conductor paths of an insulating substrate by means of a laser beam. This method only provides for determining the continuity of the conductor paths and does not provide for the measurement of the resistance and/or capacitance of these paths. The same applies to the test method described in document EP-1233275A 2(Nihon Densan Read K.K). The document proposes various methods for determining the continuity of the path based on whether these cross-overs (i.e. whether they pass through the substrate) are mentioned above. However, these methods cannot measure the resistance or capacitance of the conductor path, i.e. the measurement operation for obtaining the resistance or capacitance value. The continuity of the cross-path may be measured as follows: electrons are extracted from the first end of the path by the photoelectric effect, collected by a collector carried to a unique potential, and the intensity of the current flowing through a circuit linking the collector to the second end of the path is measured. This current intensity is compared with the known current intensity already obtained by the corresponding path of a fault-free substrate ("gold plate"), and the continuity or discontinuity of the crossing path is deduced from this comparison. Continuity of the non-crossing path can be measured according to two methods. In both methods, the path to be tested is capacitively coupled to the plates on opposite sides of the substrate. According to a first method, electrons are extracted from the end of the path by the photoelectric effect, then a current is generated between the path and the plate by the collector, and the intensity of this current is measured and integrated and a value is obtained, which is compared with the value previously obtained by the gold plate. According to a second method, the same procedure is applied, but the intensity of the charging current through the capacitance formed between the path and the plate is measured by performing two laser shots that extract the charges from each end of the conductor path by the photoelectric effect. Again, the results obtained here were compared with the known results obtained with gold plates.

This document EP-1236052B 1(Vaucher Christophe) describes a test method which can be used to measure the resistance of a conductor path of an insulating matrix. According to this method, a board having a plurality of conductor areas subjected to be individually brought to any adjustable potential is arranged to face the conductor to be tested and to be close thereto. A particle beam, in particular a laser beam, is then applied to the conductor at a first point to extract electrons from the photoelectric effect. In parallel, electrons are injected into a second point of the conductor, thereby causing current to flow through the conductor. The current intensity between these two points is then measured and the resistance of the conductor is deduced therefrom by applying ohm's law: u ═ R × I.

However, the implementation of this method is rather complicated. Indeed, the pulse duration of the laser used is typically on the order of nanoseconds. Therefore, measuring the current I ═ U/R over this period of time requires an electronic device operating at several GHz, which is very expensive. Furthermore, operating at these high frequencies means difficulties in linking with the self-inductance of the circuit under test, which is a nuisance for the measurement.

Given the state of the art, the present invention is directed to a method for testing or measuring electrical components and a system for implementing such a method, which do not require direct measurement of the current intensity between two test points, and thus do not require electronic devices operating at several GHz, which represent difficulties linked to the self-inductance of the circuit under test, which are troublesome and at the same time expensive to perform.

This object is achieved by providing a method for testing or measuring an electrical component, wherein a particle beam is applied to a first location of the electrical component; releasing electric charges under the effect of the application of these particle beams; collecting the released charges by a collector; measuring the collected charge value; and deriving an electrical characteristic of the electrical component from the measurement of the collected charge values.

Disclosure of Invention

According to one embodiment, the particle beam is a laser beam.

According to one embodiment, the electrical component is a conductor path, which is integrated in or placed on an insulating substrate and contains metal pads at each of its two ends.

According to one embodiment, the first location is a metal pad.

According to one embodiment, the metal pad is of type C4.

Advantageously, the measurement of the value of the collected charge is ensured by the device for measuring the collected charge and containing therein the capacitance, while the measurement of the value of the collected charge is carried out by measuring the charge of this capacitance.

According to one embodiment, the reset unit synchronizes the measurement of the collected charge values in accordance with the pulses of the particle beam.

According to one embodiment, charge is injected into the second position of the electrical element by compensating for the loss of charge extracted by the action of the particle beam, and by measuring the value of the injected charge by means for measuring the injected charge.

According to one embodiment, the capacitance of the electrical element may be derived from the value of the injected charge.

According to an embodiment, the electrical characteristic is a resistance or a capacitance of the electrical element.

According to an embodiment, the electrical characteristic is an electrical continuity of the electrical component or an electrical insulation of the electrical component with respect to another electrical component.

The invention also relates to a method for manufacturing an interconnection support or an electronic circuit arranged on an interconnection support, the interconnection support or the electronic circuit comprising electrical components, the method comprising a step of testing or measuring all or part of the electrical components of the interconnection support or the electronic circuit according to the testing or measuring method according to the invention.

The invention also relates to a system for testing or measuring an electrical component, comprising means for generating a beam of particles to be applied to a first location of the electrical component, the application of the beam to the first location being such as to release an electrical charge; a collector of the released charge; means for measuring the collected charge value; and means for deriving an electrical characteristic of the electrical component from the measurement of the collected charge value.

According to one embodiment, the system comprises means for generating a pulse preceding the start of the beam impact, said pulse constituting the input of the reset unit of the means for measuring the magnitude of the charge collected by the collector.

According to one embodiment, the system comprises a source, which is equipped to inject charges into the second position of the electrical element, by compensating for the loss of the extracted charges under the action of the particle beam.

According to one embodiment, the system includes means for measuring the magnitude of the injected charge.

According to one embodiment, the system includes a capacitor, and the collected charge value is measured by measuring a charge of the capacitor.

According to one embodiment, the system is arranged to derive an electrical characteristic, which is a resistance or a capacitance of the electrical element.

According to one embodiment, the system is arranged to derive an electrical characteristic which is an electrical continuity of the electrical component or an electrical insulation of the electrical component with respect to another electrical component.

According to the invention, the value of the charge collected varies mainly according to two parameters, namely the resistance and the capacitance of the electrical element. If the capacitance or resistance value of the element is known, or if one of these two parameters can be neglected, for example by carrying out a double measurement, or by a good estimation of one of these from the design data of the electrical element to be tested, the charge value collected during the application of the particle beams will only vary in accordance with the resistance and/or capacitance, i.e. the electrical characteristics desired for the measurement operation. It is therefore not necessary to measure the resistance of the electrical element, from the intensity of the current flowing through the element, as this is the case described in the aforementioned document EP-1236052B 1. The measurement electronics can thus be simplified considerably. The electronic device may alternatively operate with a passband of about kHz, i.e. about 6 times lower than the passband of the measuring electronics operating by measuring the current intensity flowing through the conductor path as in the state of the art.

Drawings

The invention may be better understood, given the relevance, but not limited to, of an embodiment of the method according to the invention and the following description of the system according to the invention, with reference to the accompanying drawings, in which:

fig. 1A schematically illustrates an embodiment of a system according to the present invention, for measuring the resistance and/or capacitance of a C4-BGA type conductor path across a substrate,

fig. 1B schematically shows an embodiment of a system according to the invention, for measuring the resistance and/or capacitance of non-crossing conductor paths of the type C4-C4,

fig. 2 is an electrical diagram of the conductor path and the collector as a whole in a system according to the invention,

figures 3A and 3B illustrate the voltage evolution of a metal pad and the evolution of collected charge during and after laser firing as a function of time for different resistance values of the path and a first capacitance value of the path,

fig. 4A and 4B illustrate the voltage evolution of a metal pad and the evolution of collected charge during and after laser firing as a function of time for different resistance values of the path and a second capacitance value of the path,

fig. 5A and 5B illustrate the voltage evolution of the metal pad and the evolution of the collected charge during and after a laser shot as a function of time for different resistance values of the path and a third capacitance value of the path,

fig. 6 illustrates the manner in which the charge collected by the collector of a system according to the present invention varies, according to the resistance of the path, for different values of the capacitance of the path,

figure 7 is a functional diagram of a measurement system according to the invention,

figure 8A is a functional diagram of a particular embodiment of a reset unit of the system according to the present invention,

figure 8B illustrates the different signals generated by a particular embodiment of the reset unit of the system according to the present invention,

FIG. 9 is a functional diagram of a particular embodiment of a measurement device of the system according to the present invention, which is located on the ground side, and

FIG. 10 is a functional diagram of a particular embodiment of a measurement device of the system according to the present invention, located on the collector side.

Description of the main elements

1 base body

2 conductor path/electric element

3 conductor path/electrical component

4-point plate

4-1 point plate

4-2 point plate

5-point plate

6 laser beam/particle beam

7 Generator

8 is grounded

9 collector

10 first device

11 infinite electron source

12 second device

13 is grounded

14 calorimeter

15 measuring device

16 pulses

17 reset unit

18 get card

19 delay device

20 delay device

21 retarder

22 delay device

23 moulding device

24 laser pulses

25 circuit

26 first filter

27 amplifier

28 second filter

29 follower

30 drift correction signal

31 signal

32 amplifying the signal

33 switching circuit

34 Command

35 vacuum box

36 charge measurement circuit

37 first filter

38 signal

39 amplifier

40 second filter

41 signal

42 follower

43 drift correction signal

Detailed Description

The method and system according to the invention can be used for testing electrical components such as active or passive components, which can be discrete or integrated on a substrate, such as: printed circuit semiconductor chips or electronic circuits on glass substrates used to make flat screens.

The method and system according to the invention also allow for determining the electrical characteristics of the electrical component under test, in particular the electrical continuity, resistance or capacitance of the electrical component under test, or the electrical insulation of the component in relation to another component or a group of other components linked in between. The electrical element may be, for example, a metal pad having a plane or any other geometric shape at each end thereof, as an integrated or adapted conductor path placed on an insulating substrate. The insulating substrate may be, for example, a substrate of very high density printed circuit, or HDI printed circuit (high density interconnect), which is used in most portable electronic devices, such as mobile phones, MP3 players, CD or DVD readers, or digital cameras, like microprocessors or memories in the packaging composition of semiconductor chips, while the corresponding printed circuit is called "IC package substrate" or "chip carrier". These substrates contain a high density of printed metal conductor paths, sometimes less than tens of microns wide, with the spacing between the two paths being narrower than half of that, and the test-accessible metal paths having dimensions less than 100 microns. However, the invention is also applicable to any type of substrate having conductor paths arranged on one or more steps, such as substrates constituting LCD or plasma flat screens, and semiconductor chips before packaging. Furthermore, the invention is further applicable to testing operations via cards equipped with components, called field tests, to testing operations for continuity and insulation, and to testing operations for passive component values such as resistors or capacitors.

In practice, the measurement of the resistance and/or capacitance of the conductor paths of an insulating substrate is aimed at checking the continuity and insulation of the paths, in particular for testing the interconnection network constituted by all or all the conductor paths laid on the insulating layers of the substrate and linked by the metallized holes or tracks.

In the embodiment of fig. 1A and 1B, the substrate 1 of the test operation is a chip carrier of the spark gap type, which is a standard printed circuit pitch of about 1 mm for carrying semiconductor chip-type electronic components with a far higher connection density to points. Each conductor path 2, 3 of the base body 1 is located at its surface on its upper or lower side (path 3) or crosses it (path 2) and links both faces of the base body. Each end of the conductor path includes a metal pad. The metal pads are located on the upper (dot plates 4, 4-1, 4-2) and lower (dot plate 5) faces of the substrate 1. Each point plate located on the upper side of the substrate can be particularly provided for mounting the chip using flip-chip technology. Each of the pads may be, for example, of the type C4, in the sense of a "controlled collapse chip connection". In this case, it is made of a lead metal alloy-dyed type, or equivalent lead-free alloy. Each dot plate 5 on the lower side of the base body is of the BGA type, which means a "ball grid array". The metal pads of the C4 type and the metal pads of the BGA type may constitute interconnection contacts arranged in a matrix form on the surface of the base 1.

The conductor paths subject to the resistance measurement process according to the invention are C4-C4 type non-crossing paths linking two C4 type metal pads on the upper side of the substrate, BGA-BGA type non-crossing paths linking two BGA type dot plates on the lower side of the substrate, or C4-BGA type crossing paths linking a C4 type metal pad on the upper side of the substrate to a BGA type dot plate on the lower side of the substrate, or more generally any other type of crossing path.

According to a particular embodiment of the invention as shown in fig. 1A, a particle beam 6 is applied at the location of the crossing conductor path 2, which consists of a C4 type spot plate 4 constituting the end of the path whose continuity, resistance and/or capacitance is to be measured. The particle beam is, for example, a laser beam 6 supplied by a pulsed laser of the YAG type, frequency-multiplied by a factor 5, the pulse duration of which is preferably in the order of a few nanoseconds. The laser energy is measured using a calorimeter 14 linked to a device 15 for measuring the laser energy.

A horizontal machine plate is placed in the path of the laser beam 6 close to the substrate 1 but substantially parallel to this substrate 1. This plate is brought to a positive voltage Vc by means of a generator 7 placed at the ground 8. In this way, the plate constitutes a collector 9, which is able to collect the electrons released by the conductor paths when they are subjected to the laser beam 6. The collector 9 is linked, according to the invention, to a first device 10 for measuring the collected charge, as will be described later in the description according to the invention.

To measure the resistance and/or capacitance of the crossing path 2, a metal pad 5 at the other end of the path 2 is linked to an infinite electron source 11. This source is located below the path 2 metal pad 5 and above the underside of the substrate 1. These may be constituted by a wiring board adapted to address the electronic device, an anisotropic conductive elastomer, a microstrip cathode, a carbon nanotube cathode or a second laser beam producing the inverse photoelectric effect. According to the invention, this is linked to the second measuring device 12 and to the ground 13. I.e. the first measuring device 10, the second measuring device 12 will be further described later in the description according to the invention.

When the short-wavelength, practically ultraviolet, radiation beam 6 strikes the spot plate 4, electrons are released from the spot plate by the photoelectric effect. These electrons are collected by the collector 9.

Under the action of the particle beam 6, a current flows through the dipole formed by the metal pad 4 and the collector 9. This current depends on the energy of the beam and on the collector 9 voltage according to law i (v) related to the spot plate geometry and the probability of space charge occurrence.

Fig. 2 shows the equivalent circuit consisting of the conductor path 2 placed with the point plate 4 and the collector 9 carried to a positive voltage Vc as a whole. The conductor path 2 can be modeled by a capacitor C and a resistor R circuit, which is subjected to a voltage V. It is assumed that the electron source 11 is connected to ground. The current flowing between the metal pad 4 and the collector 9 in the case of a planar metal pad and a space charge present complies with the blue mil rule and conforms to the following equation:

I(V)＝kV3/2

if this is given the characteristics of the dipole in question, this is simply given by the information, since this is specific to the geometry of the dipole and to the geometry of the beam 6.

Numerical simulations may be performed on the basis of the particular electronic circuit. This circuit conforms to the relationship:

I＝K(V_c-V)^3/2

the parameters used in the simulation operation may be as described in table 1 below.

TABLE 1

M (electronic quality)	9×10-31kg
		q (electronic charge)	1.6×10-19C
ε 0 (free space capacitance)	8.84643×10-12F/m
		Vc (collector voltage)	60V
d (distance between dot plate/collector)	100μm
		D (laser beam diameter)	100μm
Jdiode (Current Density between Point plate and collector)	1.6×105A/m2

Idiode (the charge that can be collected during the pulse, the metal pad placed on ground)	1.28mA
		Speed of light	300,000km/s
E (laser)	10μJ
		DI (pulse duration)	4ns
Delta (photoelectric output value)	1.00×10-5
		h (Planck constant)	6.63×10-34J/s
Lambda (photon wavelength)	213nm
		E (photon energy)	9.3×10-19J
Np (total number of photons generated by the pulse)	1.1×1013
		Ne (total number of electrons generated by pulse)	1.1×108
Photoelectricity in pulse process I	4.28mA
		Charge emitted during the pulse	17.1pC
Space charge in motion	0.15pC

Curves V1, V2, V3 and V4 in fig. 3A illustrate the evolution of the voltage Vp of the spot plate 4 in volts after a laser shock of nanosecond time t, for different resistance values R1, R2, R3, R4 and R3, R10 Ohms and R4 of the path, respectively, in a simulation taking into account the parameters of table 1. Curves V '1, V' 2, V '3 and V' 4 of fig. 4A and curves V "1, V" 2, V "3 and V" 4 of fig. 5A illustrate the evolution of the voltage Vp for the same path resistance values R1, R2, R3 and R4 as previously described, but for a path capacitance C equal to 100fF in fig. 4A and equal to 1pF in fig. 5A, and according to the same parameters as table 1. Curves Q1, Q2, Q3 and Q4 in fig. 3B illustrate the evolution of the charge Q collected in pC according to the time t in nanoseconds, with a capacitance C of 10fF for the different path values R1, R2, R3 and R4 described above, under a simulation taking into account the parameters of table 1. Curves Q '1, Q' 2, Q '3 and Q' 4 of fig. 4B and curves Q "1, Q" 2, Q "3 and Q" 4 of fig. 5B illustrate the evolution of the collected charge Q for the same path resistance values RI, R2, R3 and R4 as previously described, but equal to 100fF in fig. 4B and 1pF in fig. 5B.

For very high resistances (R1000 GOhms), the voltage Vp increases and decreases very slowly over time. In contrast, for very low resistance (R ═ 10Ohms), the voltage Vp hardly changes and remains close to 0V. For medium resistances (R1000 Ohms or 1MOhm), the voltage of the spot plate 4 increases by about 4 nanoseconds to reach a maximum value and then decreases gradually for the capacitance value tested. In all cases, the collected charge increases over time. The charge is a function of resistance. In practice, the lower the resistance, the more significant the charge collected. The potential rise during the impingement may account for the change in the collected charge.

In fig. 6, the curves QA, QB, QC, QD and QE illustrate the evolution of the charge Q collected by the collector and according to pC, according to the resistance of the path in ohms, for the following path capacitance value C: 1fF, 10fF, 100fF, 1pF and 10pF, respectively. That is, as shown in this figure, the collected charge changes with the resistance of the path. The higher the resistance, the lower the charge collected. All curves have the same profile in inverse S, so each curve has a reflection point. The lower the capacitance, the lower the reflection point.

Thus, if the charge value collected by a collector and the path capacitance are known, the resistance of the path can be derived from this. The charge value is the charge value actually flowing through each path of the test operation. The charge value can be measured directly, rather than being evaluated solely by an integrated amperage.

The same procedure can be applied to both test and non-intersecting paths.

In this case, i.e. as shown in fig. 1B, the laser beam 6 is applied at the location of the non-intersecting conductor paths 3, where resistance and/or capacitance measurement is to be performed, and more particularly at the end of the path constituted by the metal pad 4-1.

To measure the resistance and/or capacitance of the path 3, the metal pad 4-2 is linked to an infinite electron source 11. This electron source 11 is arranged, for example, on the upper side of the substrate 1, on the metal pad 4-2 of the path under consideration. The source is composed of a microstrip cathode, a carbon nanotube cathode or a second laser beam capable of generating a reverse photoelectric effect. According to the invention, this is linked to the second measuring device 12 and to the ground 13.

As in the case of fig. 1A, when the beam 6 touches the metal pad 4-1, electrons are released from the spot by the photoelectric effect. These electrons are collected by the collector 9.

The measurement principle is therefore the same as that of the crossing path described above.

FIG. 7 is a functional block diagram illustrating the measurement system according to the present invention. As shown in the figure, this system contains means for generating a positive pulse 16 supplied by the power supply of the laser, with its rising edge corresponding to the start of firing the laser shot. The system further comprises a unit 17 for resetting the measuring devices, the measuring device 12 on the ground side, the measuring device 10 on the collector side, the device 15 for measuring the energy of the laser, and an acquisition card 18. The pulse 16 constitutes the input of the unit 17 for resetting the measuring devices. The output signal T5 of the unit 17 constitutes a reset signal which is applied to the inputs of the above-mentioned devices 10, 12 and 15. The output signal T3 of the unit 17 is constituted as a signal to update the capacitance charging the device 10. The other input signals for these devices 10, 12 and 15 are from the electronics 11, the collector 9, the generator 7 and the calorimeter 14. In addition, a command 34, as described in detail below with reference to FIG. 10, may be applied to the input of the device 10. The output signals of these devices 12, 10 and 15 constitute the input signals for the acquisition card 18.

In addition to the synchronization pulse 16 at the beginning of the laser shot, the measuring device according to the invention can mean the generation of the respective square-wave signals T1, T2, T3, T4 and T5, i.e. as shown in fig. 8A. This figure is a functional diagram of the reset unit 17. T1 is a processing signal. T2 corresponds to a reset signal. T3 corresponds to a signal to recharge the collector capacitors C1, C2 and C3 as shown in fig. 10, which may be defined as follows. T4 is a signal to calibrate the measurement system. According to a specific embodiment of the present invention, the reset unit comprises four delays 19, 20, 21 and 22, and means 23 for shaping the signal T2. The first delay 19 generates the signal T1 from the synchronization pulse 16 at the start of the laser shot. The second delay 20 can generate the signal T2 from the same pulse 16. The third delayer 21 generates the signal T3 from the signal T1. The fourth delayer 22 generates the signal T4 from the signal T2. Means 23 for shaping the signal T2 may be provided for generating the signal T5 from the signal T2.

The sync pulse 16 at the beginning of the laser shot is used to trigger signals T1 and T2. The laser pulse 24 itself occurs 210 microseconds after the rising edge of the pulse 16. The falling edge of the T1 triggers the pulse T3, which is used to recharge the capacitors C1, C2, and C3 (fig. 10). The falling edge of the signal T2 triggers the signal T4, which is used to calibrate the measurement system. The signal T2 determines the length of the reset period of the device circuit arranged as a charge amplifier.

According to a particular embodiment of the measuring system as shown in fig. 8B, it is particularly aimed at drawing the laser with a flash at the beginning of which the rising edges of the above-mentioned signals T1 and T2 are synchronized with the rising edge of the synchronization pulse 16. The rising edge of the signal T3 is synchronized with the falling edge of the signal T1. The period length of this signal T1 is equal to 1 millisecond. The period length of the signal T2 is 190 microseconds. The period length of the signal T3 is 200 microseconds.

Fig. 9 is a functional diagram of the measuring device 12 of the system according to the invention, which is located on the ground side. The device 12 comprises a circuit 25 for measuring the charge, a first filter 26, a gain 10 amplifier 27, a second filter 28 and a follower 29. At the inputs of the circuit 25, there are the reset signal T5, the charge measurement input signal from the electron source 11, and a drift correction signal 30. The output signal of the charge measurement circuit 25 is filtered by the first filter 26. The filtered signal 31 thus obtained corresponds to the output signal of the device 12. This may be amplified by the amplifier 27 and filtered again by the filter 28, delivering an amplified signal 32. The follower 29 takes the output signal filtered by the second filter, and the signal obtained at the output constitutes the input to the acquisition card 18.

In practice, the apparatus 12 comprises circuits, the first of which is an operational amplifier arranged as an integrator. The amplifier is characterized by a very high input impedance Ze and a very low input current ie. Another circuit is provided for injecting the drift correction signal 30 through a resistor into the "negative" input of the amplifier to optimize the amplifier drift. If the integrated capacitance is Ci, the sensitivity of the table as coulomb by volt is equal to Ci. This sensitivity is chosen to be equal to Ci of 10 pF. If Vs is the output voltage of the integrator after the firing, the measured electrical property Qm is Qm — Vsx 10-11C. Measurement of the magnitude of the electrical property passing through the source of infinite electrons can be performed by measuring the magnitude of the electrical property carried by a capacitive charge (or discharge) current injected through a resistor into the input of the operational amplifier.

Fig. 10 shows a measuring device 10 of the system according to the invention, which is located on the collector side 9. The device comprises a switching circuit 33, a high impedance 0/Vc driven by a command 34; a vacuum box, the wall of which is designated 35; and, like the measuring device 12 on the ground side, the charge measuring circuit 36, to which the signal T5 and the drift correction signal 43 are applied; a first filter 37 delivering a signal 38 representative of the charge measured by the collector 9; a gain 10 amplifier 39; a second filter 40 delivering an amplified signal 41 of factor 10; and a follower 42. The operation of this device is similar to that of the measuring device 12. However, the circuit allows for calculating the charge value collected by the collector 9. Indeed, the output voltage Vs is given by Vs ═ 1/Cix ═ ixdt, where ═ ixdt is the magnitude of the electrical property Q collected at the system input. Thus, S-Q/V-Ci and Ci-10 pF. During the reset of the measuring circuit, if the command 34 is inactive, the collector 9 is carried from the circuit 33 to the voltage Vc via the resistors R1 and R2. During the laser pulse, the command 34 is still inactive, and the circuit 33 insulates the collector 9 from the generator 7. The capacitances C1, C2, and C3 are then delivered with the current necessary to make the measurement. After the laser pulse, if the command 34 is inactive, the signal T3 can recharge the capacitors C1, C2 and C3 through the circuit 33. During the reset of the measurement circuits described above, if the command 34 is active, the collector 9 is carried by the circuit 33 to the ground via resistors R1 and R2. During the laser pulse, the command 34 is still active, this circuit 33 insulating the collector 9 from the generator 7. Each of the capacitors C1, C2, and C3 then delivers the current necessary for making the measurement. After the laser pulse, if the command 34 is active, the signal T3 discharges the capacitors C1, C2 and C3 again through the circuit 33. This configuration can be used to reset the potential of each path as described below.

As with the device 12, the device 10 is implemented to include circuitry: the first circuit is an operational amplifier that is arranged as an integrator. The amplifier is characterized by a very high input impedance Ze and a very low input current ie. Another circuit is available for injecting the drift correction signal 43 through a resistor into the "negative" input of the amplifier to optimize the amplifier drift. If the integrated capacitance is Ci, the sensitivity of the table as coulomb by volt is equal to Ci. In the case of measurements on the collector side, this sensitivity is chosen to be equal to Ci, 10-11F. If Vs is the output voltage of the integrator after the firing, the measured electrical property Qm is Qm — Vsx 10-11C. The measurement of the electrical magnitude through the collector can be performed by measuring the electrical magnitude carried by a resistor through a capacitive charge (or discharge) current injected into the input of the operational amplifier.

Finally, according to the invention, three measurements are performed for each path.

The first measurement is directed to checking the continuity of the path. This first measurement is typically made in conjunction with a resistance measurement of the path. The first measurement can be performed by utilizing the photoelectric effect on any one of the metal pads of the path, as well as an electron source on the other metal pad. This measurement is based on the charge collected at each shot, which depends on the resistance of the path. The measurement operation can be performed by each of the measurement devices as described above. The measurement of the resistance can be performed with knowledge of the properties of the opto-electric dipole and/or based on the resistance of the circuit by using an abacus or given the calculation of the collected charge. At each impingement, the incident energy is calibrated by measurement of the energy. For high values of path resistance and/or capacitance, the measurement is performed after the time evolution of the charge collected from the measurement circuit. One way to easily obtain the capacitance value of the path is also to measure the charge collected when the path is fully charged after an impulse. Indeed, if Q is the charge, V is the voltage of the collector and C is the capacitance of the path, so C equals Q/V. To be able to use this relationship, it is necessary to know the initial potential of the path, which is done by "resetting" the potential of the path. For this purpose, the collector is placed at the ground during this early stage, and this is done prior to discharge strike(s), as described above in connection with the command 34.

The second measurement is directed to checking the primary isolation of the path with respect to all other paths of the interconnect network linked to the same potential or between the paths.

Finally, a third measurement operation is directed to subsequently checking the secondary insulation of this path compared to all other separately considered paths. This third measurement is only performed if the results of the second measurement indicate that the path is not properly insulated within the interconnect network.

According to the present invention, a system for measuring electrical quantities with an accuracy of about 10% and a dynamic range of 10-13 to 10-8 coulombs is thus provided.

It will be clear that the invention is not limited to the specific embodiments described above.

In particular, for the practice of the present invention, a continuous laser may be used instead of the pulsed laser. Other non-laser devices may be used to introduce electron release at the conductor path level, such as an electron or ion gun. And thus not by the photoelectric effect to release electrons. The measurement principle remains the same.

Claims (19)

1. A method for testing or measuring electrical components (2, 3), characterized in that:

applying a particle beam (6) to a first location (4, 4-1) of an electrical component (2, 3), releasing charges under the effect of applying the particle beam (6), the released charges being collected by a collector (9), measuring the collected charge values, and deriving electrical characteristics of the electrical component from the measurement of the collected charge values.

2. The method according to claim 1, characterized in that said particle beam (6) is a laser beam.

3. Method according to claim 1 or 2, characterized in that the electrical components (2, 3) are conductor paths which are integrated in or placed on the insulating base (1) and which contain metal pads at their two ends.

4. A method according to claim 3, characterized in that said first location is a metal pad (4, 4-1).

5. The method according to claim 3 or 4, wherein the metal pad (4, 4-1) is of the type C4.

6. Method according to any of the preceding claims, characterized in that the measurement of the collected charge value is ensured by means (10) for measuring the collected charge and including a capacitor, while the measurement of the collected charge value is performed by measuring the charge of the capacitor.

7. Method according to any of the preceding claims, characterized in that a reset unit (17) synchronizes the measurement of said collected charge values in accordance with the pulses (16) of said particle beam (6).

8. Method according to any of the preceding claims, characterized in that charges are injected into the second position (4-2, 5) of the electrical component (2, 3) so as to compensate for the loss of the charge extracted under the action of the particle beam, and in that the value of the injected charges is measured by means for measuring the injected charges (12).

9. The method of claim 8, wherein the capacitance of the electrical component is derived from the injected charge value.

10. A method according to any preceding claim, wherein the electrical characteristic is the resistance or capacitance of the electrical component.

11. The method of any one of claims 1 to 9, wherein the electrical characteristic is electrical continuity of the electrical component or electrical insulation of the electrical component with respect to another electrical component.

12. A method for manufacturing an interconnect carrier or an electronic circuit arranged on an interconnect carrier, said interconnect carrier or electronic circuit comprising electrical components, characterized by the step of testing or measuring all or part of the electrical components of said interconnect carrier or said electronic circuit according to the testing or measuring method of any of claims 1 to 11.

13. A system for testing or measuring electrical components (2, 3), characterized in that it comprises the following items:

means for generating a particle beam (6) to be applied to a first location (4, 4-1) of an electrical element (2, 3), said beam (6) being applied to said first location for releasing an electric charge,

a collector (9) of the released charges,

means (10) for measuring the value of the collected charge, and

means for deriving electrical characteristics of said electrical component from measurements of said collected charge values.

14. The system according to claim 13, characterized by means for generating a pulse (16) preceding the start of said beam impact, said pulse (16) constituting the input of a reset unit (17) of said means (10) for measuring the magnitude of the charge collected by said collector (9).

15. The system according to any of claims 13 or 14, comprising a source (11) configured to inject charges into the second positions (4-2, 5) of the electrical elements (2, 3), thereby compensating for the loss of the extracted charges under the action of the particle beam.

16. A system according to claim 15, characterized by means (12) for measuring the magnitude of the injected charge.

17. A system according to any of claims 13 to 16, comprising a capacitor, and wherein the collected charge value is measured by measuring the charge on the capacitor.

18. A system according to any of claims 13 to 17, wherein the system is arranged to derive an electrical characteristic which is the resistance or capacitance of the electrical component.

19. A system according to any of claims 13 to 17, wherein the system is arranged to derive an electrical characteristic which is the electrical continuity of the electrical component or the electrical insulation of the electrical component with respect to another electrical component.