JP4087098B2 - Ultrasonic inspection equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention provides an ultrasonic inspection apparatus for inspecting abnormalities such as internal defects and peeling of semiconductor chips, metals, ceramic parts, etc. using ultrasonic waves.In placeIn particular, ultrasonic inspection equipment suitable for inspecting abnormalities easily, quickly and more precisely.In placeRelated.
[0002]
[Prior art]
Inspection of fine structures such as semiconductor chips (integrated circuits: IC) using ultrasonic waves is performed by inspecting the state of solder that joins the functional surface of a semiconductor chip and a wiring board, and the filling material filled in the gap between them. Done for the purpose.
[0003]
As one of such inspection methods, a single-eye ultrasonic transducer is mechanically scanned in water while irradiating the inspection object with ultrasonic waves from the transducer through the water, propagating through the inspection object and returning as an echo. There is a type in which an ultrasonic wave is captured by the transducer and a signal obtained thereby is processed to determine a state of an inspection target.
[0004]
[Problems to be solved by the invention]
What is currently becoming a problem with such an inspection method is that it takes time and labor to perform mechanical scanning with water immersion, and in the case of a semiconductor chip, the chip cannot be used after the inspection. The connection terminals are becoming increasingly narrow in area and pitch, and the current inspection accuracy may be insufficient in the ability to discriminate abnormalities.
[0005]
The ultrasonic transducer as described above can be manufactured by forming a piezoelectric material such as zinc oxide or tin oxide as a main part of the ultrasonic transducer. However, a certain film thickness is required to ensure detection sensitivity. However, practically, when the film thickness is large, the upper limit of the frequency of the generated ultrasonic wave is limited. The frequency is mostly linked to the detection resolution, and therefore leads to a lack of abnormality discrimination capability.
[0006]
If a material with high conversion sensitivity is selected as the piezoelectric material, the film thickness may be made thinner. Therefore, it is understood that a higher resolution can be achieved by increasing the driving frequency, but it is general to form without variation. Is difficult.
[0007]
  The present invention has been made in consideration of the above-described situation, and an ultrasonic inspection apparatus for inspecting abnormality such as a connection portion between a semiconductor chip and a wiring board using ultrasonic waves.In placeCan be easily and quickly inspected, and an ultrasonic inspection device capable of higher resolution.PlaceThe purpose is to provide.
[0008]
[Means for Solving the Problems]
  In order to solve the above problems, an ultrasonic inspection apparatus according to the present invention includes a substrate,A semiconductor integrated circuit formed on the substrate, a common electrode formed on the back side of the substrate,A plurality of piezoelectric layers independently formed in a matrix on the common electrode, and a plurality of upper electrodes respectively formed on the piezoelectric layersAndThe piezoelectric layer has barium titanate or lead zirconate titanate and has a thickness of 0.1 μm to 100 μm.An ultrasonic transducer, a plurality of contact terminals having a needle-like structure, connected to the contact terminals, a drive unit for generating a drive voltage from any of the contact terminals, and connected to the contact terminals; A detection unit for detecting, from the plurality of contact terminals, an electrical signal returned from the inspection target to the contact terminal due to the generated drive voltage; the detected electrical signal and a position of the arbitrary contact terminal; And a processing unit that performs processing for visualizing the state of the inspection target, and the contact terminals of the inspection device are provided corresponding to the upper electrodes of the ultrasonic transducer, respectively.It is characterized by that.
[0009]
That is, barium titanate or lead zirconate titanate is used as the material for the piezoelectric layer film. These materials have a large electromechanical coupling coefficient and higher conversion efficiency between electrical energy and mechanical vibration energy than zinc oxide, and are therefore suitable for generation and detection of ultrasonic waves. Furthermore, since the dielectric constant is larger than that of zinc oxide, when it is pulse-driven, for example, it is excellent in electrical matching with a pulse power source.
[0010]
The film thickness is 0.1 μm to 100 μm by utilizing the high conversion efficiency. Thereby, the frequency of the ultrasonic wave generated by the piezoelectric layer can be increased to, for example, about 20 MHz, and a sufficiently high resolution can be achieved. More practically, the film thickness is preferably about 0.5 to 30 μm.
[0011]
When barium titanate is used as the piezoelectric material, the Curie temperature is slightly lower (about 130 ° C.) than that of lead zirconate titanate. More preferably, the Curie temperature is raised.
[0012]
In addition, as a deposition method for forming a piezoelectric layer of barium titanate and lead zirconate titanate, physical vapor deposition such as sputtering, solution coating such as sol-gel, MOCVD (metal organic chemical vapor deposition), etc. The chemical vapor deposition method can be used. These piezoelectric films may be a polycrystalline film or a film formed by epitaxial growth, but it is more preferable to align the crystal orientation by using epitaxial growth or the like because higher piezoelectric conversion characteristics can be obtained. As another method, the piezoelectric film can be formed in advance by reducing the thickness of the piezoelectric film to the predetermined thickness. For this purpose, a polishing or cutting method can be used. In this case, the piezoelectric body thinned by polishing or the like can be bonded onto the common electrode by a predetermined method (described later).
[0013]
In addition, as materials for the common electrode and the upper electrode, noble metals such as Pt and Ir, or SrRuO₃Examples thereof include a conductive oxide film. SrRuO₃The conductive oxides such as the above have the disadvantage that the electrical resistance is slightly higher than noble metals, but the interface consistency with the piezoelectric film as described above is good and mechanically difficult to peel off There is. For example, sputtering can be used to form the electrodes.
[0014]
As a method of manufacturing a plurality of piezoelectric elements in a matrix using a piezoelectric thin film formation technique, for example, a piezoelectric film may be deposited only in a desired region using a mask during sputtering film formation. Alternatively, after depositing a film on the entire surface, an unnecessary portion of the film may be removed by a method such as chemical etching. In general, the method using chemical etching is more preferable because it enables finer processing with higher dimensional accuracy.
[0016]
  Also,Ultrasonic transducerThe machineIt is formed on the back surface of a semiconductor chip on which an integrated circuit is formed.. PressureIf the area of the electric body is set to, for example, about 500 μm × 500 μm or less, it is possible to sufficiently cope with the narrowing of the terminals to be detected for abnormalities.
[0018]
  Also,The inspection device performs ultrasonic inspection in combination with the above ultrasonic transducer.SuperSignal exchange between the upper electrode of the acoustic transducer and the inspection deviceTheBy contact terminals with needle-like structureThe ThisWith such a combination, the ultrasonic inspection, TenHigher resolution can be achieved.
[0019]
  For the contact terminal, for example, a sharp field emission cold cathode, more preferably a transfer mold cold cathode can be used. These electrodes can realize sufficient electrical contact with the narrow area upper electrode.. SuperCombine with acoustic transducerFor,The contact terminals of the ultrasonic inspection device are provided corresponding to the upper electrodes of the ultrasonic transducer.The
[0028]
DETAILED DESCRIPTION OF THE INVENTION
  BookAs an embodiment of the invention, the common electrode of the ultrasonic transducer has an interface compound layer at the interface with the formed piezoelectric layer. This interface compound layer functions as an adhesive layer between the common electrode and the piezoelectric layer. When the piezoelectric body is formed in advance by thinning it by polishing or cutting, stable adhesion with the common electrode is required in a subsequent process. For this reason, an interface compound layer is used.
[0029]
In order to form the interface compound layer, an electrostatic bonding method is used. Examples of the electrostatic bonding layer include glass (preferably glass having mobile ions), water glass, SiO 2₂Al, Ta, Ti, Ni, Si, Mo, Cr, Ge, Ga, As, Kovar, Fe, Mg, beryllium, and the like can be used. The thickness of the layer is preferably 1 to 100 atomic layers. This is because the adhesiveness is saturated when it exceeds 100 atomic layers.
[0030]
Further, at the time of bonding, the surface roughness of the piezoelectric body is set to 1% or less of its thickness (0.1 μm to 100 μm, more preferably 0.5 μm to 30 μm), and it becomes an interface compound layer. It is preferable to set the surface roughness of the adhesive layer in the same manner, because adhesion is improved and stable adhesion is achieved.
[0031]
Furthermore, without using the electrostatic bonding method, the substrate (common electrode) and the polarization-treated piezoelectric layer may be bonded by electrostatic attraction resulting from the polarization, so that a flat bonding state with the common electrode can be obtained. Easy to get. In this case, if a metal layer formed by sputtering is formed on the piezoelectric layer, the adhesion is further increased. Further, there is an advantage that the upper electrode can be stably formed on the piezoelectric body by bringing the piezoelectric body into a polarized state even after the piezoelectric body is bonded to the common electrode. Furthermore, this can also prevent a decrease in sensitivity and resolution due to the undulation of the piezoelectric layer and the nonuniform thickness of the interface compound layer.
[0032]
  In the following, embodiments of the present invention will be described with reference to the drawings, taking semiconductor chip inspection as an example.In the following description, the first embodiment, the second embodiment, the fourth embodiment, and the fifth embodiment are not embodiments of the invention, regardless of the description. Each is a reference example, and based on these reference examples, the third embodiment that remains as an embodiment of the present invention will be described.
(First embodiment)
  FIG. 1 is a configuration diagram illustrating a configuration of an ultrasonic inspection apparatus according to the first embodiment of the present invention. As shown in the figure, this ultrasonic inspection apparatus includes an ultrasonic transducer 9, a signal generation unit 1, a drive element selection unit 2, a signal detection circuit 4, amplifiers 5a, 5b,..., 5i, and an A / D converter 6a. , 6b,..., 6i, the signal processing unit 7, the display device 10, and the cuvette 110. The inspection container 110 contains water 15 and is immersed in the water 15 so that the ultrasonic transducer 9 and the semiconductor chip 11, the wiring substrate 13, and the connection solder 12 (hereinafter referred to as a semiconductor) are inspection objects (ultrasonic irradiation objects). The chip 11, the wiring board 13, and the connection solder 12 are collectively referred to as “semiconductor chip 11 etc.”).
[0033]
The ultrasonic transducer 9 includes a plurality of piezoelectric transducers 41a, 42a, 43a,..., 49a, 50a, 50b,. Is determined by the selection of the drive element selection unit 2, and the drive signal from the signal generation unit 1 is guided by a conducting wire. In addition, electrical signals generated by the respective piezoelectric converters 41a and the like are guided to the signal detection circuit 4 by conductive wires. When the piezoelectric conversion unit 41 a or the like is electrically driven, an ultrasonic wave is generated due to the property as a piezoelectric body, and the generated ultrasonic wave reaches the semiconductor chip 11 through the water 15. The ultrasonic echo reflected by the semiconductor chip 11 or the like is input again to the piezoelectric converter 41a or the like via the water 15, and thereby each piezoelectric converter 41a or the like generates an electrical signal.
[0034]
The signal generator 1 generates a pulse or continuous drive signal so that the piezoelectric converter 41a and the like generate ultrasonic waves. The generated drive signal is guided to the drive element selector 2. The drive signal selection unit 2 selects one or a plurality of piezoelectric conversion units 41a to be driven and guides the drive signal derived from the signal generation unit 1 to the selected piezoelectric conversion unit 41a.
[0035]
The signal detection circuit 4 detects an electric signal generated by the piezoelectric conversion unit 41a and the like. Among the detected electric signals, a plurality of necessary signals for inspection are led to amplifiers 5a, 5b,.
[0036]
The amplifier circuits 5a, 5b,..., 5i amplify the guided electric signal and supply it to the A / D converters 6a, 6b,. The A / D converters 6 a, 6 b,..., 6 i perform A / D conversion on the derived electrical signals and guide them to the signal processing unit 7.
[0037]
The signal processing unit 7 processes the digital signals derived from the A / D converters 6a, 6b,..., 6i and generates information for visualizing the state of the inspection target. The generated information is guided to the display device 10. The display device 10 displays the guided information.
[0038]
The inspection container 110 is a container for immersing the semiconductor chip 11 or the like to be inspected and the ultrasonic transducer 9 in the water 15.
[0039]
FIG. 2 is a diagram showing a cross-sectional structure of the piezoelectric transducer 41a and the like. As shown in the figure, the piezoelectric converter 41a and the like have a ground electrode 122, an interface compound layer 123, a piezoelectric layer 124, and an upper electrode layer 125 on the substrate 121 from the bottom. Among these, at least the substrate 121 and the ground electrode 122 are provided in common to all the piezoelectric transducers 41a and the like. For the substrate 121, for example, single crystal or polycrystalline silicon, epoxy, ceramic, SUS, or other metal can be used. The formation of the piezoelectric conversion portion 41a and the like as shown in FIG. 2 can be performed by appropriately selecting the method already described.
[0040]
An inspection operation of the ultrasonic inspection apparatus shown in FIG. 1 will be described. A signal for driving the piezoelectric conversion unit 41a and the like is generated by the signal generation unit 1, and is guided to the piezoelectric conversion unit (piezoelectric conversion unit 46a in the figure) selected by the drive element selection unit 2. As a result, the piezoelectric conversion unit 46a generates an ultrasonic wave U, and the generated ultrasonic wave is irradiated onto the semiconductor chip 11 and the like using the water 15 as a propagation medium.
[0041]
The ultrasonic wave U irradiated to the semiconductor chip 11 etc. is refracted on the surface of the semiconductor chip 11 and further proceeds, for example, reflected by the connecting solder 12 where the defect 14 is generated and becomes an echo again, the semiconductor chip 11 and the water 15 again. To the piezoelectric transducer 46a and the like.
[0042]
Thereby, an electrical signal is generated in the piezoelectric transducer 41a and the like. The generated electrical signal is guided to the signal detection circuit 4 and detected. The signal detection circuit 4 guides electrical signals (in the figure, generated by the piezoelectric converters 41a,..., 50a) necessary for the inspection from the detected ones to the amplifiers 5a,. The amplifiers 5a,..., 5i amplify the guided signals and supply them to the A / D converters 6a,. Further, the signal A / D converted by the A / D converters 6a,.
[0043]
In the signal processing unit 7, every time switching between the drive element selection unit 2 and the signal detection circuit 4 is performed, a signal is taken in from the A / D converters 6 a,. The process of imaging the distribution state of the reflected echo intensity from is performed. The result is displayed on the display device 10. If the connection solder 12 has a defect (solder peeling or the like) 14, the reflection intensity of the ultrasonic wave U increases, and the position and degree can be known from the processing result of the signal processing unit 7.
[0044]
In this embodiment, high-frequency driving is possible due to the structural and material characteristics of the piezoelectric conversion unit 41a and the like, so that high-resolution inspection can be performed, and in addition, the piezoelectric conversion unit 41a and the like are matrixed. Therefore, the inspection can be performed more efficiently than the mechanical scanning of the piezoelectric transducer.
[0045]
In this embodiment, the acoustic medium is water 15 and the material is different from the semiconductor chip 11 or the like to be inspected. As a result, ultrasonic refraction occurs on the surface of the semiconductor chip 11. Therefore, the signal processing unit 7 specifies the ultrasonic path in the semiconductor chip 11 in consideration of this refraction.
[0046]
(Second Embodiment)
FIG. 3 is a configuration diagram illustrating the configuration of an ultrasonic inspection apparatus according to the second embodiment of the present invention. In the figure, the same reference numerals are given to components already described, and description of the configuration and operation is omitted. In this embodiment, unlike the first embodiment, ultrasonic irradiation to the inspection object is not performed through water but using a shoe material.
[0047]
  Shoe material due to the coupling 1716The semiconductor chip 11 and the like are in flat contact with each other, so that the ultrasonic wave emitted from the piezoelectric conversion portion 41a and the like of the sound wave transducer 9 travels almost without being refracted on the surface of the semiconductor chip 11 as shown. Therefore, it is not necessary to perform processing by the signal processing unit 7 in consideration of refraction, and processing can be performed more easily.
[0048]
The shoe 17 and the semiconductor chip 11 and the like are brought into a flat contact with the coupling 17, and as a result, the ultrasonic wave generated by the piezoelectric conversion portion 41 a and the like of the acoustic wave transducer 9 is almost on the surface of the semiconductor chip 11 as shown in the figure. Proceed without refraction. Therefore, it is not necessary to perform processing by the signal processing unit 7 in consideration of refraction, and processing can be performed more easily.
[0049]
Moreover, since it is not necessary to prepare a test container for containing water and the test target is not immersed in water, the target can be used as usual even after the test. Therefore, it is possible to use not only the sampling inspection but also the ultrasonic inspection in the air easily.
[0050]
Also in this embodiment, high-frequency driving is possible due to the structural and material characteristics of the piezoelectric conversion unit 41a and the like, so that high-resolution inspection can be performed, and the piezoelectric conversion unit 41a and the like are formed into a matrix. Therefore, the inspection can be performed more efficiently than the mechanical scanning of the piezoelectric transducer.
[0051]
(Third embodiment)
FIG. 4 is a configuration diagram illustrating a configuration of an ultrasonic inspection apparatus according to the third embodiment of the present invention. In the figure, the same reference numerals are given to components already described, and description of the configuration and operation is omitted. In this embodiment, the piezoelectric converter is directly formed on the back surface (opposite side of the functional surface) of the semiconductor chip 11a or the like to be inspected, and the upper electrode is contacted by the contact terminal to supply the drive voltage and take out the generated voltage. It is what you do.
[0052]
As shown in FIG. 4, a common electrode 58 is formed on the back surface of the semiconductor chip 11a by sputtering, for example, and piezoelectric layers 60a, 60b, 60c, 60d,... Are formed on the common electrode 58 in a matrix. ing. Upper electrodes 59a, 59b, 59c, 59d,... Are formed on the piezoelectric layer 60a and the like, respectively. The piezoelectric layer 60a and the like can be formed by sputtering using a mask pattern, for example. The arrangement / formation of each piezoelectric conversion unit may correspond to the arrangement of the connection solder 12 in order to further simplify the signal processing.
[0053]
The drive voltage is supplied through the upper electrode 59a and the generated voltage is taken out by the contact terminals 61a, 61b, 61c. The contact terminals 61a and the like can be scanned and moved by the scanning movement mechanism 8. In this figure, the number of contact terminals is three, but the number may be set as appropriate. Further, the contact terminals 61a and the like can be specifically used as described above.
[0054]
In the signal processing unit 7a, the position given to the contact terminal 61a and the like by the scanning movement mechanism 8 is obtained as information, and the semiconductor chip 11a and the connection solder 12 are joined by this and information from the detection signal by the ultrasonic waves Ua, Ub, Uc and the like. Processing for imaging the distribution state of reflected echo intensity from the interface is performed.
[0055]
Also in this embodiment, it is not necessary to prepare a test container for containing water, and the test object is not immersed in water, so that the object can be used as usual even after the test. Therefore, it is possible to use not only the sampling inspection but also the ultrasonic inspection in the air easily.
[0056]
Similarly, high-frequency driving is possible because of the structural and material characteristics of the piezoelectric conversion portion, so that high-resolution inspection can be performed. The method for supplying the drive voltage and taking out the generated voltage by using the contact with the piezoelectric conversion unit by the contact terminal 61a or the like described here uses a conductor in the first and second embodiments. It can replace with the connection with the piezoelectric conversion part 41a etc. which were used, and can also be utilized.
[0057]
(Fourth embodiment)
FIG. 5 is a configuration diagram illustrating a configuration of an ultrasonic inspection apparatus according to the fourth embodiment of the present invention. In the figure, the same reference numerals are given to components already described, and description of the configuration and operation is omitted. In this embodiment, inspection is performed by mechanically scanning an ultrasonic transducer.
[0058]
As shown in the figure, this ultrasonic inspection apparatus includes an ultrasonic transducer 9a, a signal generation unit 1a, a signal detection circuit 4a, an amplifier 5a, an A / D converter 6a, a signal processing unit 7b, a display device 10, and an inspection container. 110a. Water 15 is accommodated in the inspection container 110a, and the ultrasonic transducer 9a and the semiconductor chip 11 to be inspected (object to be irradiated with ultrasonic waves) are disposed by being immersed in the water 15.
[0059]
The ultrasonic transducer 9a has a structure in which an electrode layer 29, a piezoelectric layer 30, and an upper electrode layer 31 are sequentially laminated on a concave substrate surface, and this laminated structure functions as a piezoelectric conversion unit. A driving signal from the driving unit 1a is guided to the piezoelectric conversion unit by a conducting wire. In addition, the electrical signal generated by the piezoelectric conversion unit is guided to the signal detection circuit 4a by a conducting wire. When the piezoelectric conversion unit is electrically driven, an ultrasonic wave U is generated due to the property as a piezoelectric body, and the generated ultrasonic wave reaches the semiconductor chip 11 through the water 15. Ultrasonic echoes from the semiconductor chip 11 and the like are input again to the piezoelectric converter via the water 15, and the piezoelectric converter generates an electrical signal.
[0060]
The drive unit 1a generates a pulse-like or continuous drive signal so that the piezoelectric conversion unit generates ultrasonic waves. The signal detection circuit 4a detects an electrical signal generated by the piezoelectric conversion unit. The detected electrical signal is guided to the amplifier 5a. The subsequent A / D converter 6a and display device 10 are the same as those already described.
[0061]
The signal processing unit 7b generates information for visualizing the state of the inspection object by obtaining and processing the digital signal derived from the A / D converter 6a and the position given to the ultrasonic transducer 9a by the scanning movement mechanism 8a. It is. The generated information is guided to the display device 10.
[0062]
The scanning movement mechanism 8a is provided as a mechanism for setting the position of the ultrasonic transducer 9a, and information on the setting position is guided to the signal processing unit 7b. The inspection container 110 a is a container for immersing the semiconductor chip 11 to be inspected and the ultrasonic transducer 9 a in the water 15.
[0063]
The laminated structure of the ultrasonic transducer 9a will be further described. The electrode layer 29 can be formed so as to function also as an adhesive layer using electrostatic attraction. The material can be selected from Cr, Ta, Si and the like. The piezoelectric layer 30 can be formed by thinning and bonding a material such as that already described to a thickness of, for example, about 10 μm. In the figure, when a conductive material (for example, doped Si single crystal, or only the surface layer may be doped) is used for the substrate under the electrode layer 29, the electrode layer 29 is not formed. Also good.
[0064]
The inspection operation of the ultrasonic inspection apparatus shown in FIG. 5 will be described. The position of the ultrasonic transducer 9a is determined by the scanning movement mechanism 8a, and a signal for driving the ultrasonic transducer 9a is generated by the drive unit 1a. Thereby, the ultrasonic transducer 9a generates an ultrasonic wave U, and the generated ultrasonic wave is irradiated to the semiconductor chip 11 and the like using the water 15 as a propagation medium.
[0065]
The ultrasonic wave U irradiated to the semiconductor chip 11 etc. is refracted on the surface of the semiconductor 11 and further proceeds. For example, the ultrasonic wave U is reflected by the connection solder 12 in which the defect 14 is generated and becomes an echo, and the semiconductor chip 11 and the water 15 again. To the ultrasonic transducer 9a.
[0066]
As a result, the ultrasonic transducer 9a generates an electrical signal. The generated electric signal is guided to the signal detection circuit 4a and detected. The signal detection circuit 4a guides the detected electrical signal to the amplifier 5a. The amplifier 5a amplifies the guided signal and supplies it to the A / D converter 6a. Further, the signal A / D converted by the A / D converter 6a is taken into the signal processing unit 7b.
[0067]
In the signal processing unit 7b, the digital signal guided from the A / D converter 6a and the position given to the ultrasonic transducer 9a by the scanning movement mechanism 8a are obtained and processed, and the bonding interface between the semiconductor chip 11 and the connecting solder 12 is processed. The process of imaging the distribution state of the reflected echo intensity from is performed. The result is displayed on the display device 10. Such a process can be performed every time the position of the ultrasonic transducer 9a is determined by the scanning movement mechanism 8a.
[0068]
In this embodiment, high-frequency driving is possible because of the structural and material characteristics of the ultrasonic transducer 9a, and therefore high-resolution inspection can be performed. Further, for example, the piezoelectric layer 30 can be more uniformly formed on the substrate by adhesion using an electrostatic force, so that it is possible to prevent deterioration of sensitivity and resolution due to poor uniformity.
[0069]
Even in this embodiment, since the acoustic medium is water 15 and the material is different from the semiconductor chip 11 or the like to be inspected, the ultrasonic wave U is refracted on the surface of the semiconductor chip 11. Therefore, the signal processing unit 7b specifies the ultrasonic path in the semiconductor chip 11 in consideration of this refraction.
[0070]
(Fifth embodiment)
FIG. 6 is a configuration diagram illustrating a configuration of an ultrasonic inspection apparatus according to the fifth embodiment of the present invention. In the figure, the same reference numerals are given to components already described, and description of the configuration and operation is omitted. In this embodiment, an ultrasonic wave is generated in an inspection object using laser light, and the inspection object is inspected by detecting and processing the echo.
[0071]
As shown in the figure, this ultrasonic inspection apparatus includes an intensity-modulated laser light source 101, an irradiation optical system 102, a vibration displacement detector 71, amplifiers 5a, 5b,... 5i, A / D converters 6a, 6b,. 6i, a signal processing unit 7, a display device 10, and a scanning movement mechanism 8b. Laser light from the irradiation optical system 102 positioned by the scanning movement mechanism 8b is irradiated to the semiconductor chip 11 or the like to be inspected.
[0072]
The intensity-modulated laser light source 101 generates intensity-modulated laser light (may be intermittent laser light as a special case of intensity modulation), and the generated laser light is guided to the irradiation optical system 102. The irradiation optical system 102 irradiates a predetermined position of the semiconductor chip 11 to be inspected in a spot shape with the guided laser beam. In order to irradiate a predetermined position, the irradiation optical system 102 is scanned and moved by the scanning movement mechanism 8b. Note that energy conversion occurs in the semiconductor chip 11 due to the laser light irradiation, and ultrasonic waves are generated.
[0073]
The vibration displacement detector 71 detects an ultrasonic wave of each part that returns as an echo to the surface of the semiconductor chip 11 in a non-contact manner and converts it into an electrical signal. The principle of detection is to measure and detect the vibration displacement of the surface due to the ultrasonic wave returning to the surface of the semiconductor chip 11 by the phase change of the laser beam irradiated from the vibration displacement detector 71 and reflected. Among the detected electric signals, a plurality of necessary signals for inspection are led to amplifiers 5a, 5b,. The A / D converters 6a, 6b,..., 6i, the signal processing unit 7, and the display device 10 which are the subsequent configurations are as described above.
[0074]
The scanning movement mechanism 8b moves the irradiation optical system 102 and the vibration displacement detector 71 synchronously, and simultaneously supplies positional information of the irradiation optical system 102 and the vibration displacement detector 71 to the signal processing unit 7a. .
[0075]
The inspection operation of the ultrasonic inspection apparatus shown in FIG. 6 will be described. The laser light generated by the intensity-modulated laser light source 101 is guided to the irradiation optical system 102, and the irradiation optical system 102 irradiates a predetermined position of the semiconductor chip 11 to be inspected in a spot shape. The position is set by the scanning movement mechanism 8b. Thereby, an ultrasonic wave is generated from the surface of the semiconductor chip 11 at the above position.
[0076]
The ultrasonic wave generated on the surface of the semiconductor chip 11 travels through the semiconductor chip 11 and is reflected by, for example, the connecting solder 12 in which the defect 14 is generated to become echoes Ua, Ub, Uc and again on the surface of the semiconductor chip 11. Reach.
[0077]
Accordingly, the vibration displacement detector 71 generates a plurality of electrical signals corresponding to the ultrasonic waves of the respective parts that have returned to the surface of the semiconductor chip 11 based on the above principle. Of the generated electric signals, the electric signals necessary for the inspection are guided to the amplifiers 5a,. The amplifiers 5a,..., 5i amplify the guided signals and supply them to the A / D converters 6a,. Further, the signal A / D converted by the A / D converters 6a,..., 6i is taken into the signal processing unit 7a.
[0078]
In the signal processing unit 7a, the position given to the irradiation optical system 102 and the like by the scanning movement mechanism 8b is obtained as information, and the distribution of the reflected echo intensity from the bonding interface between the semiconductor chip 11 and the connection solder 12 is obtained based on this position and the acquired signal. A process of imaging the state is performed.
[0079]
In this embodiment, an ultrasonic generation source having a very small area can be formed at an accurate position on the irradiation target by making the laser beam generated intermittently or intensity-modulated into a spot shape. Thereby, high-resolution detection becomes possible by capturing the echo.
[0080]
Moreover, since it is not necessary to prepare a test container for containing water and the test target is not immersed in water, the target can be used as usual even after the test. Therefore, it is possible to use not only the sampling inspection but also the ultrasonic inspection in the air easily.
[0081]
【The invention's effect】
As described above in detail, according to the present invention, the ultrasonic nondestructive inspection with high resolution can be realized easily and quickly due to the structural and material characteristics of the ultrasonic transducer. In addition, according to the present invention, an ultrasonic generation source having a very small area can be made on the surface of the inspection object, so that high resolution of ultrasonic inspection can be realized.
[Brief description of the drawings]
[Figure 1]Reference exampleThe block diagram explaining the structure of the ultrasonic inspection apparatus which concerns on.
FIG. 2 is a diagram showing a cross-sectional structure of a piezoelectric transducer 41a and the like shown in FIG.
[Fig. 3]Another reference exampleThe block diagram explaining the structure of the ultrasonic inspection apparatus which concerns on.
FIG. 4 The present inventionThe fruitThe block diagram explaining the structure of the ultrasonic inspection apparatus which concerns on embodiment.
[Figure 5]Yet another reference exampleThe block diagram explaining the structure of the ultrasonic inspection apparatus which concerns on.
[Fig. 6]Yet another reference exampleThe block diagram explaining the structure of the ultrasonic inspection apparatus which concerns on.
[Explanation of symbols]
  DESCRIPTION OF SYMBOLS 1 ... Signal generation part 1a ... Drive part 2 ... Drive element selection part 4, 4a ... Signal detection circuit 5a, 5b, ... 5i ... Amplifier 6a, 6b, ..., 6i ... A / D converter 7, 7a, 7b ... Signal processing unit 8, 8a, 8b ... scanning movement mechanism 9, 9a ... ultrasonic transducer 10 ... display device 11, 11a ... semiconductor chip 12 ... connecting solder 13 ... wiring board 14 ... defect 15 ... water 16 ... shoe material 17 ... cup Runt 29 ... Electrode layer 30 ... Piezoelectric layer 31 ... Upper electrode layer 41a, 42a, 43a, 45a, 46a, 49a, 50a, 50b, 50h ... Piezoelectric transducer 59a, 59b, 59c, 59d ... Upper electrode 60a, 60b, 60c, 60d ... Piezoelectric layer 61a, 61b, 61c ... Contact terminal 71 ... Vibration displacement detector 101 ... Intensity modulated laser light source 102 ... Irradiation optics System 110, 110a ... Inspection vessel 121 ... Substrate 122 ... Ground electrode 123 ... Interface compound layer 124 ... Piezoelectric layer 125 ... Upper electrode layer

Claims (1)

A substrate,
A semiconductor integrated circuit formed on the substrate;
A common electrode formed on the back side of the substrate;
A plurality of piezoelectric layers independently formed in a matrix on the common electrode;
A plurality of upper electrodes respectively formed on the piezoelectric layer,
The piezoelectric layer includes barium titanate or lead zirconate titanate, and an ultrasonic transducer having a thickness of 0.1 μm to 100 μm;
A plurality of contact terminals having a needle-like structure;
A drive unit connected to the contact terminal for generating a drive voltage from any of the contact terminals;
A detection unit connected to the contact terminal and detecting an electrical signal returned from the inspection target to the contact terminal due to the generated drive voltage from the plurality of contact terminals;
An inspection apparatus comprising a processing unit that performs a process of visualizing the state of the inspection object from the detected electrical signal and the position of the arbitrary contact terminal ;
The contact terminal, the ultrasonic inspection apparatus characterized by being provided corresponding to the upper electrode of the ultrasonic transducer before dangerous査device.

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