JP4667233B2 - Dry ultrasonic inspection method and ultrasonic inspection equipment - Google Patents

Description

  The present invention relates to an ultrasonic flaw detection method for inspecting an inspection object such as an electronic component by a dry method.

  As one means for realizing the recent trend of small and thin products, electronic parts having electrodes on the lower surface such as BGA and CSP are increasing in order to reduce the mounting area. When the lower surface electrode component is used, the bonding portion with the substrate cannot be observed by optical means, so that another means for assuring quality is required.

  Conventionally, as a method for observing the inside of an electronic component, there are a method using X-rays and an ultrasonic flaw detection method. In the method using X-rays, a great effect is obtained for inspections such as disconnection, short circuit, and volume abnormality, but it is not suitable for inspection of joints such as peeling. In the ultrasonic flaw detection method, ultrasonic waves of 1 MHz or higher are mainly used, and ultrasonic waves of 1 MHz or higher are largely attenuated in the air and hardly propagate. Therefore, the inspection target is immersed in a liquid ultrasonic transmission medium such as water, and the ultrasonic transmission / reception is performed on the inspection target via the ultrasonic transmission medium, and the inspection is performed, but the inspection target is immersed in the liquid ultrasonic transmission medium. As a result, in addition to the problem that the electrode material to be inspected is eluted as ions into the ultrasonic transmission medium and the reliability is lowered, processes such as a rinsing process and a drying process after the inspection are increased at the production site.

Further, (Patent Document 1) discloses a dry ultrasonic flaw detection method in which an inspection target is inspected without being immersed in an ultrasonic transmission medium. This is because, as shown in FIG. 7A, only a bottom surface is closed with a polymer film 50 and a medium container 3 containing the ultrasonic transmission medium 2 and the polymer film 50 therein is used. As shown in FIG. 7 (b), the frame-like connecting body 51 provided at the bottom of 3 is pressed against the wiring board 4 to accommodate the semiconductor chip 5 as an inspection object inside the connecting body 51. The inside of the connection body 51 is connected to the decompression device 52, the closed space formed by the wiring substrate 4, the connection body 51, and the polymer film 50 is decompressed, and the polymer film 50 is brought into close contact with the semiconductor chip 5. Ultrasonic waves are transmitted from the ultrasonic probe 8 to the semiconductor chip 5 via the ultrasonic transmission medium 2 and the polymer film 50, and reflected echoes are received by the ultrasonic probe 8 for flaw detection.
JP 2003-177117 A

  However, in the dry ultrasonic inspection method described in (Patent Document 1), another electronic component 6 is mounted near the semiconductor chip 5 as shown in FIG. In this case, a closed space cannot be formed by the wiring substrate 4, the coupling body 51, and the polymer film 50. Therefore, even if the pressure is reduced by the pressure reducing device 52, the polymer film 50 cannot be brought into close contact with the semiconductor chip 5, and a flaw detection inspection cannot be performed.

  In addition, as shown in FIG. 8B, when the inspection target range of the semiconductor chip 5 is large and the polymer film 50 can be adhered to only a part of the semiconductor chip 5, the flaw detection in the ranges A and B is performed. The inspection cannot be performed.

  Further, as shown in FIG. 8C, when the closed space formed by the wiring board 4, the coupling body 51, and the polymer film 50 is decompressed, the surrounding space connected to the exhaust passage is preferentially exhausted. Thus, the outer portion close to the periphery of the polymer film 50 first forms a close contact state. For this reason, there is a case where the air layer 53 remains without being able to obtain the required adhesion at a place where it is desired to evacuate between the surface of the semiconductor chip 5 and the polymer film 50. In particular, as shown in FIG. 8D, when there are fine irregularities on the surface of the semiconductor chip 5, it becomes more difficult to obtain adhesion in the depressions 5A. In such a case, the air layer 53 partially remains between the surface of the semiconductor chip 5 and the polymer film 50, and ultrasonic waves are very difficult to transmit through the air layer. I can't.

  The present invention provides a dry ultrasonic flaw detection method and an ultrasonic flaw detection apparatus capable of inspecting an entire inspection object even when the inspection object is attached to a substrate with high mounting efficiency or when the inspection object range is large. Aim to do.

  In the dry ultrasonic inspection method according to claim 1 of the present invention, an ultrasonic wave is applied to an inspection object via an ultrasonic transmission medium, and an ultrasonic wave reflected by the inspection object is received to ultrasonically inspect the inspection object. In this case, the inspection object is covered with a liquid resin, the resin is cured to form a resin layer that covers the inspection object, the inspection object with the resin layer formed is immersed in an ultrasonic transmission medium, and an ultrasonic probe is formed. A flaw detection inspection is performed by propagating an ultrasonic wave from a child to an inspection object through the ultrasonic transmission medium and the resin layer.

  In the dry ultrasonic inspection method according to claim 2 of the present invention, ultrasonic waves are applied to an inspection object via an ultrasonic transmission medium, and ultrasonic waves reflected by the inspection object are received to ultrasonically inspect the inspection object. In this case, the inspection part to be inspected is exposed and accommodated in a storage case, and at least the inspection part to be inspected is covered with a liquid resin to cure the resin to form a resin layer. The inspection object in which the resin layer is formed is immersed in an ultrasonic transmission medium, and ultrasonic inspection is propagated from the ultrasonic probe to the inspection object through the ultrasonic transmission medium and the resin layer, thereby performing a flaw detection inspection. And

  According to a third aspect of the present invention, there is provided an ultrasonic flaw detection apparatus that applies ultrasonic waves to an inspection object via an ultrasonic transmission medium, receives ultrasonic waves reflected by the inspection object, and ultrasonically inspects the inspection object. An ultrasonic flaw detector, which contains an inspection target, a storage case for holding a liquid resin that is supplied so as to cover the entire surface of the inspection target and is cured to form a film, and an ultrasonic transmission medium. A medium containing container capable of immersing the inspection object after curing of the resin together with the storage case; and an ultrasonic wave is emitted to the inspection object through the ultrasonic transmission medium and the resin layer in contact with the ultrasonic transmission medium An ultrasonic probe is provided.

  In the dry ultrasonic inspection method according to claim 4 of the present invention, an ultrasonic transmission medium is brought into contact with an inspection object via a resin layer, and the ultrasonic probe superimposes the inspection object via the ultrasonic transmission medium. When performing the ultrasonic inspection, the inspection portion to be inspected is exposed and accommodated in a housing case, the opening portion of the housing case is covered with a lid member formed with an opening in which the inspection target region to be inspected is opened, and the lid A liquid resin is supplied from the opening of the member so as to cover the region to be inspected, and cured to form a resin layer that covers the region to be inspected, exceeding the inspection case in which the housing case and the resin layer are formed. A flaw detection inspection is performed by immersing the ultrasonic wave in an acoustic wave transmission medium and propagating ultrasonic waves from an ultrasonic probe to an inspection target through the ultrasonic wave transmission medium and the resin layer.

  In the ultrasonic flaw detection apparatus according to claim 5 of the present invention, an ultrasonic transmission medium is brought into contact with an inspection target through a resin layer, and an ultrasonic probe ultrasonically scans the inspection target through the ultrasonic transmission medium. An ultrasonic flaw detector for inspecting, in which an accommodation portion that exposes and accommodates the inspection portion to be inspected (and an opening that covers the opening of the accommodation case and opens the inspection object region to be inspected is formed. A lid member, a resin holding member that is provided between the inspection object and the lid member and holds the liquid resin supplied so as to cover the inspection portion from the opening of the lid member, and an ultrasonic transmission medium After the resin is cured, the medium container that can immerse the inspection object together with the storage case, and the ultrasonic wave is contacted with the ultrasonic transmission medium and the ultrasonic wave is transmitted to the inspection object via the ultrasonic transmission medium and the resin layer. Ultrasonic probe to fire Characterized in that a and.

  The dry ultrasonic flaw detection method according to claim 6 of the present invention is the method according to claim 1, wherein the liquid resin is isobrene rubber, styrene-butadiene copolymer rubber, ethylene- The main component is propylene-diene rubber, chloroprene rubber, acrylic rubber, acrylonitrile-butadiene rubber, or silicone rubber.

  According to the dry ultrasonic inspection method and the ultrasonic inspection apparatus of the present invention, the inspection object that requires precise inspection such as the electronic component of the mounting board is dry, and ultrasonic inspection suitable for implementation at the production site is performed. realizable.

Hereinafter, each dry ultrasonic flaw detection method of the present invention will be described based on each embodiment shown in FIGS.
(Embodiment 1)
1A and 1B show (Embodiment 1) of the present invention.

  Here, the semiconductor chip 5 to be inspected is mounted on the wiring board 4. In addition to the semiconductor chip 5, an electronic component 6 is mounted in the vicinity of the mounting position of the semiconductor chip 5 on the wiring substrate 4 as an electrical component to which the inspection target is attached.

  At the time of dry ultrasonic flaw detection, as shown in FIG. 1A, the entire wiring board 4 is covered with a liquid resin, and the resin is cured to form the resin layer 1. The resin layer 1 is a resin whose main component is any one of isobrene rubber, styrene-butadiene copolymer rubber, ethylene-propylene-diene rubber, chloroprene rubber, acrylic rubber, acrylonitrile-butadiene rubber, and silicone rubber.

  The wiring board 4 covered with the resin layer 1 is immersed in the ultrasonic transmission medium 2 accommodated in the medium accommodating container 3 as shown in FIG. The ultrasonic probe 8 is so reflected that the ultrasonic wave transmitted from the ultrasonic probe 8 is reflected with high sensitivity at the position of the target depth of the semiconductor chip 5 and received by the ultrasonic probe 8. The distance between the semiconductor chip 5 and the semiconductor chip 5 is adjusted and set, the ultrasonic wave is emitted, the ultrasonic wave reflected by the semiconductor chip 5 is received by the ultrasonic probe 8, and the purpose of the examination site is determined from the time difference between transmission and reception. The state of the depth position is inspected. After the inspection, the resin layer 1 is removed and taken over to the next process.

  In this way, the liquid resin is supplied to the surface of the semiconductor chip 5 and cured, and the entire wiring substrate 4 is covered with the resin layer 1, thereby ensuring the reliability between the surface of the semiconductor chip 5 and the resin layer 1. Even if there is unevenness on the surface of the semiconductor chip 5, uncured resin enters the recess and hardens, so that the air layer 53 as in the conventional case does not occur, and the accurate ultrasonic wave of the semiconductor chip 5 is generated. Can perform flaw detection inspection.

  In addition, even when the electronic component 6 is mounted in the vicinity of the semiconductor chip 5, the resin layer 1 is formed according to the shape of the semiconductor component 5. Wherever the semiconductor chip 5 is present, ultrasonic flaw detection can be performed.

  Here, the resin layer 1 is formed on the entire surface of the wiring substrate 4 on which the semiconductor chip 5 and the electronic component 6 are mounted. However, the resin layer 1 can be formed only on the upper surface of the semiconductor chip 5 to perform a dry inspection. .

(Embodiment 2)
FIG. 2 shows (Embodiment 2) of the present invention.
In (Embodiment 1), the entire wiring board 4 is covered with the resin layer 1, but in this (Embodiment 2), the housing layer 10 is used to form the resin layer 1 on the back surface of the wiring board 4. Only the difference is not. The same as (Embodiment 1).

  A holding member 11 that supports the wiring board 4 is provided on the inner periphery of the opening of the housing case 10 that covers the back surface of the wiring board 4. The wiring substrate 4 on which the semiconductor chip 5 to be inspected is mounted is placed on the holding member 11 with the mounting surface of the semiconductor chip 5 facing up. Then, liquid resin is supplied and covered from the upper surface of the wiring board 4 and the outer periphery of the wiring board 4 to the housing case 10 from above. And this resin is hardened and the resin layer 1 is formed. The liquid resin can be supplied by a spray method or a die coat method.

Thereafter, as shown in FIG. 2B, the wiring board 4 is immersed in the ultrasonic transmission medium 2 accommodated in the medium accommodating container 3 together with the accommodating case 10 and inspected.
Thus, by holding the board to be inspected by the holding member 11 formed in the housing case 10, even if the electronic component is the board to be inspected mounted on both sides of the board, wiring is performed even after the ultrasonic transmission medium is immersed. The flatness of the substrate 4 and the semiconductor chip 5 can be reliably maintained, and an accurate flaw detection inspection can be performed.

  Furthermore, since it is not necessary to cover the back surface of the wiring board 4 with a resin layer, the amount of necessary resin can be reduced and the running cost can be reduced. After the inspection, the resin layer 1 is removed, the wiring board 4 and the housing case 10 are separated, and the wiring board 4 is taken over to the next process.

(Embodiment 3)
3 and 4 show (Embodiment 3) of the present invention.
In the previous (Embodiment 2), the upper surface of the housing case 10 is opened so that the entire upper surface of the wiring board 4 is covered with the resin layer 1, but as shown in FIG. A lid member 12 having an opening 13 corresponding to the position of the semiconductor chip 5 is provided. A resin holding member 14 is formed around the opening 13 of the lid member 12 according to the difference in height between the surface of the wiring board 4 and the housing case 10. Others are the same as (Embodiment 2).

  In the inspection, after the wiring substrate 4 is accommodated in the accommodating case 10 and closed by the lid member 12, a liquid resin is supplied to the opening 13 provided in the lid member 12 and cured to form the resin layer 1. . Thereafter, as shown in FIG. 3B, the wiring board 4 is immersed in the ultrasonic transmission medium 2 accommodated in the medium accommodating container 3 together with the accommodating case 10 and inspected.

  In this way, the wiring substrate 4 is covered with the lid member 12 having the opening 13 corresponding to the position of the semiconductor chip 5, and the wiring substrate 4 and the lid member 12 are brought into close contact with the resin holding member 14, thereby allowing the semiconductor chip 5. Since it is only necessary to supply the liquid resin only to the position, the amount of the necessary resin can be further reduced as compared with the case of (Embodiment 2), and the running cost can be reduced.

4 (a) and 4 (b) show modifications of FIG. 3 (a).
FIG. 4A will be described. In FIG. 3A, the tip of the resin holding member 14 is in contact with the surface of the wiring board 4, but the tip of the resin holding member 14 in this modification is in contact with the outer peripheral portion of the upper surface 5 </ b> A of the semiconductor chip 5. Yes. Others are the same as those in FIG.

  FIG. 4B will be described. The tip of the resin holding member 14 of this modification is in contact with the upper surface 5 </ b> A of the semiconductor chip 5 at the tip of the resin holding member 14 corresponding to one of the two semiconductor chips 5. The tip of the resin holding member 14 corresponding to the other semiconductor chip 5 is in contact with the surface of the wiring substrate 4 so as to surround the semiconductor chip 5 in the same manner as in FIG.

  It should be noted that a minute gap corresponding to the surface roughness of the closely contacting portion remains at the place where the tip of the resin holding member 14 is in contact with the upper surface 5A of the semiconductor chip 5, but when the liquid resin is supplied By the capillary phenomenon, the resin spreads in the gap, and the wiring board 4 can be reliably sealed. Further, when the tip of the resin holding member 14 is brought into contact with the upper surface 5A of the semiconductor chip 5, the resin layer 1 is more in comparison with the case where the tip of the resin holding member 14 is brought into contact with the surface of the wiring board 4. Since it does not go under the semiconductor chip 5, it is easy to remove the resin layer 1 after the inspection.

(Embodiment 4)
FIG. 5 shows (Embodiment 4) of the present invention.
In the previous inspection process of (Embodiment 3), a liquid resin is supplied by dropping it from above and is cured as it is to form the resin layer 1, but in this (Embodiment 4), After the liquid resin 1A is supplied and before curing, the container case 10 is mounted on the vibration plate 20 for applying vibration in the XY plane direction, and a step of making the height of the liquid resin constant is added. Yes. Others are the same as (Embodiment 3).

  As described above, by adding a step of applying vibration in the XY directions before the liquid resin is cured, the thickness of the resin layer 1 formed on the upper surface of the semiconductor chip 5 can be made constant. 5 accurate ultrasonic inspections can be performed.

(Embodiment 5)
FIG. 6 shows (Embodiment 5) of the present invention.
This (Embodiment 5) shows a modification of the lid member 12 in the previous (Embodiment 3), and here, among the FIGS. 3 (a), 4 (a) and 4 (b), FIG. The case of FIG. 4B will be described as an example.

  In the lid member 12 shown in FIG. 6A, an annular thickness adjusting unit 30 and a resin containing unit 31 positioned outside the thickness adjusting unit 30 are provided around the opening 13. Others are the same as (Embodiment 3).

  Since it comprised in this way, after accommodating the wiring board 4 in the storage case 10, after closing the cover member 12, after supplying liquid resin 1A to the opening part 13 provided in the cover member 12, the opening part 13 By moving the squeegee 32 according to the size along the upper surface of the thickness adjusting unit 30, the excessively supplied liquid resin 1a is removed to the resin containing unit 31 as shown in FIG. 6B. Then, after curing, the resin layer 1 having a uniform thickness can be formed, and an accurate ultrasonic inspection of the semiconductor chip 5 can be performed.

  The thickness adjusting portion 30 and the resin accommodating portion 31 can be similarly implemented in FIGS. 3 (a) and 4 (a). 3A, FIG. 4A, and FIG. 4B, the thickness adjusting portion 30 can be widened to serve as the resin containing portion 31.

  In each of the above embodiments, the resin layer 1 has been described as being removed immediately after completion of the dry ultrasonic inspection and transferred to the next process. However, the resin layer 1 is transported to the next process while being covered with the resin layer 1. It can also be used as a transport container. In the case of FIGS. 2 (a), 3 (a), 4 (a), 4 (b), and 6, it is transported in the housing case 10 and covered with the resin layer 1. Use as a container.

  In each of the above embodiments, when supplying the liquid resin for forming the resin layer 1 on the upper surface 5A of the semiconductor chip 5, a small amount of alcohol is supplied to the upper surface 5A of the semiconductor chip 5 in advance. By reducing the space of the concave and convex recesses on the upper surface 5A, in this state, by supplying a liquid resin that later forms the resin layer 1, the air layer between the resin layer 1 and the upper surface 5A is reduced, The improvement of inspection accuracy can be expected. Specifically, isopropyl alcohol, ethanol, methanol or the like can be used as the alcohol.

  INDUSTRIAL APPLICABILITY The present invention can realize an accurate ultrasonic inspection without wetting an inspection object during a production process, and can be used for in-line inspection of an electronic board on which various semiconductor devices are mounted.

Inspection process diagram of ultrasonic flaw detection method of (Embodiment 1) of the present invention Inspection process diagram of ultrasonic flaw detection method of (Embodiment 2) of the present invention Inspection process diagram of ultrasonic flaw detection method of (Embodiment 3) of the present invention Sectional drawing of the modification of the embodiment Inspection process diagram of ultrasonic flaw detection method of (Embodiment 4) of the present invention Inspection process diagram of ultrasonic flaw detection method of (Embodiment 5) of the present invention Cross-sectional view of inspection process using a conventional ultrasonic flaw detector Sectional view showing an inspection example of the conventional example

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin layer 1a Liquid resin 2 Ultrasonic transmission medium 3 Medium container 4 Wiring board 5 Semiconductor chip (inspection object)
5A Upper surface of semiconductor chip 5 6 Electronic component 8 Ultrasonic probe 10 Housing case 11 Holding member 12 Lid member 13 Lid member opening 14 Resin holding member 20 Vibration plate 30 Thickness adjusting unit 31 Resin containing unit 32 Squeegee

Claims (6)

When the ultrasonic wave is applied to the inspection object via the ultrasonic transmission medium, the ultrasonic wave reflected by the inspection object is received and the inspection object is ultrasonically examined,
Covering the inspection target with a liquid resin and curing the resin to form a resin layer covering the inspection target,
A dry type ultrasonic inspection method in which an inspection target formed with the resin layer is immersed in an ultrasonic transmission medium, and ultrasonic waves are propagated from the ultrasonic probe to the inspection target through the ultrasonic transmission medium and the resin layer. Sonic flaw detection method. When the ultrasonic wave is applied to the inspection object via the ultrasonic transmission medium, the ultrasonic wave reflected by the inspection object is received and the inspection object is ultrasonically examined,
Exposing the inspection portion to be inspected and storing it in a storage case;
Covering at least the inspection portion to be inspected with a liquid resin and curing the resin to form a resin layer,
The inspection object in which the housing case and the resin layer are formed is immersed in an ultrasonic transmission medium, and ultrasonic waves are propagated from the ultrasonic probe to the inspection object through the ultrasonic transmission medium and the resin layer. Dry ultrasonic inspection method to inspect. An ultrasonic flaw detector that acts on an inspection object via an ultrasonic transmission medium, receives ultrasonic waves reflected by the inspection object, and ultrasonically inspects the inspection object,
A storage case that holds a liquid resin that contains a test object, is supplied so as to cover the entire surface of the test target part, and is cured to form a film;
A medium container that can accommodate an ultrasonic transmission medium and can immerse the inspection target after curing of the resin together with the storage case;
An ultrasonic flaw detector provided with an ultrasonic probe that comes into contact with the ultrasonic transmission medium and emits ultrasonic waves to an inspection object through the resin layer and the resin layer. When the ultrasonic transmission medium is brought into contact with the inspection object via the resin layer, and the ultrasonic probe ultrasonically inspects the inspection object via the ultrasonic transmission medium,
Exposing the inspection portion to be inspected and storing it in a storage case;
Covering the opening portion of the housing case with a lid member formed with an opening in which an inspection target region to be inspected is opened,
A liquid resin is supplied from the opening of the lid member so as to cover the inspection target region, and is cured to form a resin layer that covers the inspection target region,
The inspection object in which the housing case and the resin layer are formed is immersed in an ultrasonic transmission medium, and ultrasonic waves are propagated from the ultrasonic probe to the inspection object through the ultrasonic transmission medium and the resin layer. Dry ultrasonic inspection method to inspect. An ultrasonic flaw detector in which an ultrasonic transmission medium is brought into contact with an inspection object via a resin layer, and an ultrasonic probe ultrasonically inspects the inspection object via the ultrasonic transmission medium,
A storage case for exposing and storing the inspection portion to be inspected;
A lid member that covers the opening of the housing case and has an opening in which an inspection target region to be inspected is opened;
A resin holding member that is provided between the inspection object and the lid member and holds liquid resin supplied so as to cover the inspection portion from the opening of the lid member;
A medium container that can accommodate an ultrasonic transmission medium, and after the resin is cured, can infiltrate the inspection object together with the storage case;
An ultrasonic flaw detector provided with an ultrasonic probe that comes into contact with the ultrasonic transmission medium and emits ultrasonic waves to an inspection object through the resin layer and the resin layer. The liquid resin is mainly composed of any one of isobrene rubber, styrene-butadiene copolymer rubber, ethylene-propylene-diene rubber, chloroprene rubber, acrylic rubber, acrylonitrile-butadiene rubber, and silicone rubber. The dry ultrasonic flaw detection method according to claim 1, claim 2, or claim 4.

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