JP3820953B2 - Electrical circuit inspection equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric circuit inspection apparatus for measuring and inspecting electric characteristics of an electric circuit, and in particular, a probe that is required to measure a plurality of measurement points simultaneously, for example, for inspection of a semiconductor package, and the like. The present invention relates to a multi-probe and an electric circuit inspection apparatus.
[0002]
[Prior art]
Conventionally, for example, in a characteristic test of a semiconductor package, a socket type contact device is most frequently used. FIG. 6 shows an example of a socket type probe.
[0003]
That is, the conventional probe includes, for example, a guide member 94 for guiding the package portion 92 of the semiconductor package 91 and a plurality of leaf springs 95 arranged around the guide member 94 at the same pitch as the lead terminals 93 of the semiconductor package 91. Are fixed by a resin 96.
[0004]
Then, the semiconductor package 91 held by the upper guide 97 by suction is lowered along the guide material 94, so that the semiconductor package 91 is positioned, for example, as shown in FIG. 95 is in contact with each other.
[0005]
At this time, the leaf spring 95 sinks due to the bending, and scrapes off the oxide film adhering to the surface of the lead terminal 93, for example, as shown in FIG. In this way, each lead terminal 93 of the semiconductor package 91 is reliably brought into contact with each of the plate springs 95 of the probe, whereby the characteristic test of the semiconductor package 91 is performed.
[0006]
[Problems to be solved by the invention]
However, the above-described type of probe has the following problems.
For example, as shown in FIG. 8, the contact due to the bending of the leaf spring, for example, only scraping off the oxide film adhering to the surface of the lead terminal 93, did not provide reliable contact.
In addition, the lead terminals 93 have a large number of pins and a narrow pitch, and accordingly, there are disadvantages such as a complicated probe structure.
[0007]
That is, the increase in the number of pins and the narrow pitch of the lead terminals 93 lead to an increase in the number of leaf springs 95 and a decrease in the pitch between them, and there is a disadvantage that the assembly of the probe is complicated accordingly.
Therefore, there has been a demand for a probe that can achieve reliable contact and can cope with a narrow pitch, a multi-probe using the probe, and an electric circuit inspection apparatus.
[0008]
Furthermore, in the conventional method, it is a linear inspection, and for the surface inspection, the inspection must be performed while moving the inspection device little by little.
Therefore, a probe capable of collectively inspecting measurement points scattered in a planar shape, a multi-probe using the probe, and an electric circuit inspection apparatus have been desired.
[0009]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, according to the first aspect of the present invention, the probe and the probe are composed of a substrate, a spring material, a probe, a counter electrode, and a counter electrode, and both ends of the substrate are supported by the spring material. works with a counter electrode provided is provided on the back, the counter electrode provided opposite the counter electrode pulp lobe to apply a multi-probe formed in a matrix, a high frequency of opposite phase to the counter electrode There is provided an electric circuit inspection apparatus characterized by comprising control means having the above and inspection means for inspecting an electric circuit by a signal obtained by a probe .
[0010]
As a result, the oxide film can be easily and reliably removed even when the oxide film removal of the electrode to be inspected by conventional bending is insufficient.
[0012]
In addition, because of this simple configuration, it has become possible to handle inspections with a narrow pitch.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The probe used in the present invention includes a substrate, a spring material, a probe, a counter electrode, and a counter electrode.
There are various spring materials such as plates and rods, but there are many cases where an electric circuit for a counter electrode is provided on one side and an electric circuit for a probe is provided on the other side. A plate shape is preferable because it can be manufactured easily and the bending direction can be easily limited to the vertical direction only.
[0017]
In some cases, the spring material may have a shape that linearly connects the substrate and the reference position. However, in order to increase the amount of bending, it is often preferable to detour and lengthen the spring material to reduce the spring constant. .
The spring material may be any material as long as it has flexibility, but a material having a small spring constant is preferable.
However, when the spring material and the substrate are made of the same material, if the spring constant is made too small, the substrate itself may be bent, which is not preferable.
[0018]
As for the material, various materials can be used as long as they are flexible. However, if the material is conductive, it is not easy to separate the signal wiring and the control electrode, and the control in the case of common use is possible. Since the design of the system and the measurement system is not easy, the conductivity below the semiconductor is easier to implement.
[0019]
In order to easily solve the problems as described above, when a plurality of materials are combined, the above conditions are easily achieved, and thus the practicality is often high.
For example, in the case where two or more semiconductors such as silicon wafers are overlapped via an insulator and only one of them is used as a spring material, the properties of the spring material and the substrate are contradictory. It can be easily realized.
[0020]
However, since it is expensive to implement such superposition in this way, it is preferable to select appropriately considering the required performance.
Since the substrate is for attaching the probe and the counter electrode, there are few restrictions on the material, and any material can be used as long as it is difficult to deform to maintain the support function. In this case, if the spring constant is too large, the amount of deflection becomes small, which may not be preferable.
[0021]
Various materials can be used as long as they are flexible materials. However, if they are conductive materials, it is not easy to separate the signal wiring and the counter electrode. Since the design of the system and the measurement system is not easy, the conductivity below the semiconductor is easier to implement. Note that when a plurality of materials are combined, the above conditions are easily achieved, so that practicality is often high.
[0022]
For example, it is a laminate of a flexible and finely processable silicon wafer and a highly insulating resin film.
A probe cantilever characterized in that a probe supported at both ends by a spring material is provided with a probe and a counter electrode provided on the back surface of the probe, and a counter electrode is provided facing the counter electrode. It consists of a beam and a counter electrode.
[0023]
The probe may have a structure just used for measurement, but it needs to have a function to scrape off the surface that can interfere with measurement, such as an oxide film. However, it is preferable because the lifetime that can be used is extended.
The shape with a blunt tip is preferable for the service life only, but it is preferable that the tip is sharp when considering scraping performance, and this may be appropriately selected depending on the application.
[0024]
The counter electrode faces the counter electrode. The counter electrode is provided on some fixed support member, and the counter electrode and the counter electrode are opposed to each other with a certain interval when no electric force is applied.
The counter electrodes have substantially the same area, and one of them can attract the counter electrode and the Coulomb force to attract each other, or one of the counter electrode and the Coulomb force can act to make the substrate tilt.
Of course, the substrate can be further tilted by attracting either one of the counter electrode and the Coulomb force while the other counters the counter electrode and the Coulomb force.
[0025]
Further, the counter electrode can attract or attract both the counter electrode and the Coulomb force, or both can move the counter electrode and the Coulomb force to move the substrate closer to or away from the counter electrode.
Thereby, the probe can be brought into contact with or away from the electric circuit.
This is made possible by the bending of the spring material of the substrate.
[0026]
The probe need only be at the tip of the cantilever, but it need not be a complete tip and may be formed slightly inside, but it must be at least a location that is affected by deflection.
The probe material must be conductive and have some rigidity. Accordingly, copper, copper alloy, silver alloy, aluminum alloy and the like can be appropriately selected depending on the application.
The bonding of the probe needs to be highly accurate in alignment, but can be made by methods such as electroforming, alloying of the interface by annealing, and soldering.
[0027]
This counter electrode cannot be controlled properly unless lead wires are provided. However, since separate lead wires are required for the counter electrodes, it is practical to provide the counter electrodes on the two spring materials.
The counter electrode preferably has a large area in order to increase the Coulomb force. On the other hand, the large area does not allow a large pitch, and it is necessary to select an appropriate size and shape as appropriate.
[0028]
The counter electrode is provided on the support member, but is formed at a position and size where the Coulomb force against the counter electrode is increased. Therefore, it is common to provide the same or larger shape at opposite positions.
[0029]
The multi-probe of the present invention is such that such probes are arranged in a matrix. In this case, it is not necessary to provide the same number of counter electrodes as the probe, and a common electrode can be used as long as it defines the ground potential.
[0030]
In this case, since many multiprobes are produced at a narrow pitch, it is easier to produce a plate-like shape by means such as pressing, etching, or electrodeposition.
Including the multi case, any method such as conductive printing or pattern etching may be used as the method of providing electrodes and wirings on the probe.
[0031]
The control means includes at least a vibration mode, a measurement mode, and a stop mode. Of course, other modes such as a test mode may be realized.
Since the Coulomb force is proportional to the electric field, voltage control is preferable.
[0032]
In the vibration mode, the substrate is moved away from the support member, that is, the vibration is applied in a state where the electric circuit and the probe are in contact with each other, and is performed prior to the measurement mode.
[0033]
Therefore, while the counter electrode is applied with repulsive force from the counter electrode as the reference voltage of the counter electrode, a high frequency is alternately applied between the counter electrodes, and the actual voltage or current application is a sine wave, rectangular wave, Control by applying with other various waveforms.
[0034]
In the measurement mode, the substrate position is fixed with the counter electrode applied with the repulsive force from the counter electrode while maintaining the reference voltage of the counter electrode, and the stop mode may or may not be included between the vibration mode and the measurement mode. Absent.
[0035]
In the stop mode, the spring material is fixed without being bent.
In this case, no voltage is applied anywhere, but a short circuit is recommended in order to quickly enter the stop mode.
[0036]
The inspection means is performed based on a signal from the signal wiring drawn from the probe. Signal processing is inspected by measuring the resistance between two points of interest or between the point of interest and ground.
[0037]
【Example】
Example 1
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a plan view of a substrate of the same embodiment, and FIG. 4 is a conceptual block diagram of the same embodiment.
[0038]
The substrate 11 has a probe 12 at the end, a signal wiring (not shown) for extracting an electrical signal from the probe 12, a counter electrode 13 and 14 on the back side of the probe, and respective wirings 15 and 16 Is provided.
This is actually arranged in a 32 × 32 matrix.
[0039]
The substrate is composed of an insulating film, a silicon wafer for spring material sandwiching the insulating film, and a silicon wafer for maintaining strength.
An oxide film was formed on the silicon wafer for spring material.
[0040]
Next, a resist (material PMMA (polymethyl methacrylate)) was formed on the side surface of the probe, and pattern exposure was performed with ultraviolet rays using a photomask.
This photomask pattern is a pattern of a connecting pin base portion of a spring material, a pad, and a connection wiring forming portion thereof.
[0041]
Next, development was performed, unexposed portions were removed, and then the entire side surface of the probe was subjected to vapor deposition treatment with copper. By removing the resist, copper formed on the upper portion of the resist was removed, and patterning was performed. .
[0042]
As a result, the copper layer remained only in the pattern of the connecting pin base portion of the spring material, the pad, and the connection wiring forming portion thereof.
Further, a resist was formed on the side surface of the wafer probe, and pattern exposure was performed using a photomask.
This photomask pattern is a pattern that forms a connecting pin base of a spring material.
[0043]
Next, development was performed, unexposed portions were removed, and then the entire side surface of the probe was electroformed with copper to remove the resist, thereby removing chromium formed on the upper portion of the resist and patterning was performed. .
Further, it was backed on the side surface of the wafer counter electrode.
[0044]
Thereafter, a resist was formed on the side surface of the wafer counter electrode, and pattern exposure was performed using a photomask.
This photomask pattern is a pattern for forming counter electrodes, pads, and wirings thereof.
[0045]
Next, development was performed, unexposed portions were removed, and then the entire side surface of the counter electrode was vapor-deposited with copper. By removing the resist, the copper formed on the upper portion of the resist was removed, and patterning was performed. .
[0046]
Finally, a resist was formed on the side surface of the wafer probe, and pattern exposure was performed using a photomask.
This photomask pattern is a pattern composed of a substrate, a spring material, and a wiring region excluding a gap portion.
[0047]
Next, development was performed, unexposed portions were removed, then dry etching was performed, and the resist was removed to prepare a silicon wafer for a spring material.
An oxide film was formed on both sides of a silicon wafer for maintaining strength.
[0048]
Next, a resist was formed on the probe side surface, and pattern exposure was performed using a photomask.
This photomask pattern is a pattern of probes, pads, and their wiring formation portions.
[0049]
Next, development was performed, unexposed portions were removed, and then the entire side surface of the counter electrode was vapor-deposited with copper. By removing the resist, the copper formed on the upper portion of the resist was removed, and patterning was performed. .
As a result, the copper layer remained only in the pattern of the electrode, the pad, and their probe forming portions.
[0050]
Finally, the substrate side was formed by thermocompression bonding with the insulating film (material mylar, film thickness 150 μm) sandwiched between the probe side surface of the spring material silicon wafer and the strength maintaining silicon wafer.
[0051]
A probe is provided on the substrate formed in this manner, wiring is performed between the silicon wafers, and the counter electrode 18 is uniformly formed on the base material 19.
[0052]
The base material 19 is provided only at the position corresponding to the portion of the substrate 11 where the probe 12 is not provided, and only at the outside, and of course the position corresponding to the portion of the substrate 11 where the probe 12 is provided is It is a void.
[0053]
The distance between the counter electrode 18 and the substrate 11 is 0.04 mm, and the counter electrode 18 is uniformly formed on the base material 19.
A base material and a board | substrate are formed by fixing a space | interval by adhesion | attachment through PET film with a thickness of 40 micrometers.
The counter electrode 18 is uniformly formed on the substrate 19.
As a result, when 100V was applied to both the counter electrodes 13 and 14 and the counter electrode 18 to obtain a steady state, the electrodes repelled as a result.
[0054]
When placed at the inspection position of the inspection object on the measurement jig 24, the tip of the probe 12 comes into contact with the inspection object of the inspection object due to the repulsion.
Moreover, when 300V100Hz was applied between the counter electrodes 13 and 14, it oscillated with the same applied frequency and the same period as 0.02 mm in the left-right direction.
[0055]
The control means includes a measurement front-end controller 21, a personal computer 22, a controller 23, and a measurement jig 24.
The measurement jig 24 is fixed at a position where the substrate 11 contacts when the inspection object 43 is placed and fixed, and also performs an operation of providing a predetermined potential to the inspection object 43.
[0056]
FIG. 4 is a block diagram of the present invention for explaining the details of the front-end controller 21. 31 is a multi-probe and 23 is a controller. 43 is an object to be inspected, 44 is an actuator for correcting the inclination of the object to be inspected so that each probe of the multi-probe is in contact with the object to be inspected 34, and 45 is an inclination correction control circuit. Reference numeral 46 denotes a structure that supports these members.
The measurement front-end controller 21 includes a probe head control circuit 47, a decoder encoder 48, a distance control circuit 49, a substrate drive circuit 50, and a tilt correction circuit 45.
[0057]
The multi-probe 31 is controlled by a probe control circuit 47.
First, a signal emitted from the personal computer 22 in the vibration mode is encoded by the decoder encoder 48, transferred to the probe control circuit 47, and a control signal indicating that the vibration mode is ON is output to the distance control circuit 49 to control the distance. The circuit 49 outputs a control signal to contact the substrate driving circuit 50 at once, and the substrate driving circuit 50 allows a high-frequency signal current of 300 V 100 Hz to flow between the counter electrodes and between the counter electrode and the counter electrode.
On the other hand, the distance control circuit 49 outputs a correction signal to the inclination correction circuit 45 and supplies a correction current to the measurement jig 44.
The multi-probe 31 is driven by vibrating and vibrates while contacting the object to be inspected.
[0058]
Even when the probe-medium distance control is not successful, for example, when the probe is tilted, a feedback signal is generated from the personal computer 22 based on the inspection result, encoded by the decoder encoder 48, and probe control. Transfer to the circuit 47 and multi-probe tilt control are performed as described above.
[0059]
Next, a signal emitted from the personal computer 22 in the measurement mode is encoded by the decoder encoder 48, transferred to the probe control circuit 47, and a control signal indicating that the measurement mode is ON is output to the distance control circuit 49. The control circuit 49 issues a control signal for lowering the probe to the substrate driving circuit 50, and the substrate driving circuit 50 is short-circuited between the counter electrodes electrically or in a controlled manner.
[0060]
Even when the probe-medium distance control is not successful, for example, when the probe is tilted, a feedback signal is generated from the personal computer 22 based on the inspection result, encoded by the decoder encoder 48, and probe control. Transfer to the circuit 47 and multi-probe tilt control are performed as described above.
[0061]
In FIG. 6, the detailed block block diagram of the measurement part 25 is shown.
The timing for accessing each probe is based on the scanning clock 51.
As long as the probe is touched at least at the scanning timing, it may or may not be touched at other times, but it is generally not intentionally separated at times other than the scanning timing.
[0062]
This scanning clock is used as a multi-probe clock signal CLK_Y, and further input to the Y address counter 52. The Y address counter 52 has the same number of counts as the number of stages of the multi-probe Y shift register. The carry output of the Y address counter 52 is a multi-probe clock signal CLK_X and is further input to the X address counter 53. The X address counter 53 has the same number of counts as the number of stages of the multi-probe X shift register. The count output of these X and Y address counters is set as a probe address 54.
[0063]
A read output Vout from the multi-probe is input to the comparator 55. The comparator 55 binarizes using Vref 56 as a reference voltage. This binarized output is written in the recording unit of the probe control table 57 specified by the probe address 54.
[0064]
The measurement tables 57 to 59 have 1 to several pages, where one page is a temporary storage memory composed of the same number of recording units as the number of probes of the multi-probe. Each recording unit records at least six logical values such as a driving state value indicating each operation of reading, ON writing, OFF writing, or erasing, in addition to the recording data logical value read from the multi-probe.
[0065]
When accessing the multi-probe, φr (read signal), φd (erase signal), and φw (write signal) are generated so as to control the corresponding probe according to the driving state of each unit of the measurement table.
[0066]
When transferring data from a multi-probe, the probe is first scanned to a predetermined position on the recording medium.
Next, the data in the measurement tables 57 to 59 is read by the personal computer 22 via the data bus and the address bus 60 to the recording unit corresponding to the address of the probe to be read, and data processing is performed by the personal computer 22, thereby The quality is checked to determine whether it is good or bad.
[0067]
Finally, the signal emitted from the personal computer 22 in the stop mode is encoded by the decoder encoder 48, transferred to the probe control circuit 47, and a control signal is output to the distance control circuit 49. The distance control circuit 49 Then, a control signal is output to the substrate driving circuit 50, and the substrate driving circuit 50 causes a current to flow between the counter electrode and the counter electrode.
[0068]
As a result, the terminal having an oxide film on the surface could be subjected to an accurate inspection of electrical characteristics because only the inspection portion of the oxide film was removed immediately before the inspection.
[0069]
【The invention's effect】
As described above, it is possible to provide a probe that can reliably contact an oxide film or the like on the surface, can cope with a narrow pitch, and can inspect a flat surface at once, and a multi-probe and an electric circuit inspection apparatus using the probe. It was.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a multi-probe at the time of inspection according to an embodiment of the present invention.
FIG. 2 is a conceptual bottom view of the cantilever in the embodiment of FIG.
FIG. 3 is a conceptual block diagram of the embodiment of FIG.
4 is a block diagram for explaining details of a front-end controller in the embodiment of FIG. 3; FIG.
5 is a block configuration diagram for explaining details of a measurement unit in the embodiment of FIG. 3; FIG.
FIG. 6 is a side sectional view of a contact device shown for explaining the prior art and its problems.
7 is a conceptual diagram for explaining an electrical connection between a lead terminal of a semiconductor package and a leaf spring of the contact device in the contact device of FIG. 6;
FIG. 8 is a conceptual diagram for explaining the electrical connection between the lead terminal of the semiconductor package and the leaf spring of the contact device, similar to FIG. 7;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Board | substrate 12 ... Probe 13, 14 ... Counter electrode 15, 16 ... Support part 17 ... Wiring area | region 18 ... Counter electrode 19 ... Base material 20 ... Gap part 21 ... Front end controller 22 ... Personal computer 23 ... Controller 24 ... For measurement Jig 25 ... Measuring unit 26 ... Piezoelectric element 31 ... Probe 45 ... Inclination correction circuit 47 ... Probe control circuit 48 ... Decoder encoder 49 ... Distance control circuit 50 ... Substrate drive circuit 57-59 ... Measurement table 91 ... Semiconductor package 92 ... Package part 93 ... Lead terminal 94 ... Guide material 95 ... Plate spring

Claims (2)

The substrate is composed of a substrate, a spring material, a probe, a counter electrode, and a counter electrode, and the probe and the counter electrode provided on the back surface of the probe are provided on the substrate supported by the spring material at both ends, and the counter electrode control means and an electrical circuit by a signal obtained by the probe having a function opposite a counter electrode provided in pulp lobe to apply a multi-probe formed in a matrix, the opposite phase of the high frequency to the counter electrode and An electrical circuit inspection apparatus comprising inspection means for inspecting the electrical circuit. 2. The electric circuit inspection apparatus according to claim 1, wherein the electric circuit inspection apparatus has a function of applying the same potential as that of the counter electrode between the counter electrodes in addition to the function of applying the high-frequency wave having the opposite phase to the counter electrodes. .

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