JP2009135283A - Electrostatic discharge detecting element and electrostatic discharge detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic discharge detecting element such that if a dielectric breakdown due to an electrostatic discharge occurs to an IC chip in a manufacturing process of manufacturing electronic equipment such as a control unit of an engine by mounting the IC chip on a substrate, the occurrence of the dielectric breakdown can be detected with high precision, and to provide an electrostatic discharge detecting method. <P>SOLUTION: Disclosed is the electrostatic discharge detecting element 1 for detecting the dielectric breakdown due to the electrostatic discharge occurring to the IC chip in the manufacturing step of manufacturing the control unit of the engine by mounting the IC chip on the printed circuit board. The electrostatic discharge detecting element 1 is characterized in that a breakdown part is intentionally provided where a dielectric breakdown is easy to occur and can be confirmed by using equipment such as an insulation resistance tester 5, etc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrostatic discharge detection element for detecting that dielectric breakdown due to electrostatic discharge has occurred in a manufacturing process of an electronic device, and an electrostatic discharge detection method preferably performed using the detection element.

  A semiconductor device (electronic device) such as an IC chip (Integrated Circuit) is generally sensitive to static electricity. For this reason, the IC chip is mounted on a printed circuit board (printed wiring board) to produce a printed circuit board (electronic circuit board), and various electronic devices such as automobile equipment and communication equipment are produced using the printed circuit board. In the manufacturing process to be manufactured, the so-called electrostatic discharge (ESD) causes dielectric breakdown between the metal wiring pattern of the IC chip or resistors such as P-type and N-type diffusion layers, and the resulting electronic device Defective products may be generated (see, for example, Patent Document 1).

  In order to prevent such dielectric breakdown due to electrostatic discharge, in an IC chip, an electrostatic protection circuit may be provided in a power supply unit or an input / output unit inside the IC chip (see, for example, Patent Document 2).

  However, this protection circuit is not perfect, and it is difficult to select a protection circuit that can affect the electrical characteristics, limit the dimensions of the protection circuit, and respond to different electrostatic immunity (dielectric breakdown strength due to electrostatic discharge) for each IC chip. Is an obstacle.

In addition, the manufacturing process of the electronic device described above is configured by a plurality of partial processes such as a reflow processing process and an appearance inspection / repair process, and if it is possible to identify which partial process causes dielectric breakdown due to electrostatic discharge, For example, it is considered that an appropriate electrostatic discharge suppression measure such as prevention of charge / removal of charge of workers or manufacturing equipment involved in the manufacturing process can be taken.
JP-A-10-12691 JP 2000-277700 A

  However, at present, in the manufacturing process of electronic equipment, for example, even if the charge amount of an IC chip is measured, it cannot be accurately determined whether or not the charge leads to dielectric breakdown. Therefore, it is difficult to specify a partial process in which dielectric breakdown occurs in the IC chip.

  The present invention has been made to solve the above problems, and its purpose is to detect with high accuracy when dielectric breakdown due to electrostatic discharge occurs in an electronic device mounted on a substrate. It is an object of the present invention to provide a possible electrostatic discharge detection element and electrostatic discharge detection method.

  In order to solve the above problems, the invention according to claim 1 is an electrostatic discharge detection element for detecting that dielectric breakdown due to electrostatic discharge has occurred in an electronic device mounted on a substrate, The gist of the present invention is that a dielectric breakdown part is intentionally provided, and a dielectric breakdown part can be visually confirmed or confirmed by using an instrument.

  According to this configuration, the electrostatic discharge detection element is intentionally provided with a dielectric breakdown site that is likely to cause dielectric breakdown due to electrostatic discharge and that can be confirmed visually or by using a device. . For this reason, for example, in a manufacturing process in which an electronic device is mounted on a substrate and an electronic apparatus is manufactured, the substrate on which the electrostatic discharge detection element is mounted is flowed through the manufacturing process to visually check the state of dielectric breakdown of the detection element. By observing with an apparatus, when a dielectric breakdown occurs due to electrostatic discharge in the electronic device, it can be detected with high accuracy.

  According to a second aspect of the present invention, in the electrostatic discharge detection element according to the first aspect, the dielectric breakdown part is a part where a wiring pattern or a resistor provided in the detection element is separated by a predetermined gap width, or The conductor or the semiconductor provided in the detection element is set at a site insulated with an insulating film having a predetermined thickness, and the wiring pattern or the resistor or the conductor is electrically connected with the eyes or using an instrument. The gist is that it is possible to confirm that the dielectric breakdown has occurred by observing.

  According to this configuration, a dielectric breakdown portion that is likely to cause breakdown due to electrostatic discharge and that can be confirmed visually or by using a device is a wiring pattern or resistor provided in the detection element. It is set to a part where the bodies are separated by a predetermined gap width, or a part where a conductor or semiconductor provided in the detection element is insulated by an insulating film having a predetermined thickness. And it is possible to confirm that dielectric breakdown has occurred between the wiring pattern or the resistors or between the conductors by visual observation or observation with an instrument. For this reason, for example, when a dielectric breakdown due to electrostatic discharge occurs in an electronic device in a manufacturing process for manufacturing an electronic device, this fact can be detected with high accuracy by a practical and rational means. Furthermore, in the detection element, when a dielectric breakdown occurs due to electrostatic discharge at a predetermined gap width set between the wiring pattern or the resistor or a predetermined thickness set in the insulating film between the conductor or the semiconductor, It becomes possible to estimate with high accuracy that dielectric breakdown can occur even in an electronic device having the same breakdown strength. For this reason, if the electronic device is designed so as to exceed the dielectric breakdown strength, for example, the gap width between the wiring patterns or resistors is increased, or the thickness of the insulating film between the conductors is increased, It is expected (guaranteeed) with high accuracy that no defective product is generated from the electronic device obtained in the manufacturing process.

  Invention of Claim 3 is an electronic circuit board formed by mounting an electronic device on a board | substrate, Comprising: The electrostatic discharge detection element of Claim 1 or Claim 2 on the same board | substrate with the said electronic device The gist is that it is implemented.

  According to this configuration, since the electrostatic discharge detecting element according to claim 1 or 2 is mounted on the same substrate together with the electronic device to constitute the electronic circuit board, the electronic circuit board is distributed in the market. In this case, when a breakdown occurs in the detection element, it can be identified with high accuracy that the defect of the electronic circuit board is caused by electrostatic discharge, and the defective product is selectively excluded from the distribution route. It becomes possible to do.

  According to a fourth aspect of the present invention, there is provided an electronic apparatus comprising an electronic device that exhibits a predetermined function and an input / output device that exchanges signals with the outside, wherein the electronic circuit board according to the third aspect is provided. The gist is that it is installed.

  According to the configuration, in the electronic device including the electronic device and the input / output device, the electronic circuit board according to claim 3 is mounted, so that a defective product is caused for some reason in the distribution route of the electronic device as a product. If it occurs, it can be identified with high accuracy whether the cause is due to electrostatic discharge or not. That is, the electronic device can exhibit the same function as an impact sensor mounted to specify a failure due to an impact during transportation or a water detection sensor mounted to specify a failure due to water wetting.

  The invention according to claim 5 is an electrostatic discharge detection method for detecting that dielectric breakdown due to electrostatic discharge has occurred in the electronic device in a manufacturing process of mounting the electronic device on a substrate and manufacturing the electronic device, The electrostatic discharge detection in which the manufacturing process is composed of a plurality of partial processes, and the dielectric breakdown is likely to occur, and the dielectric breakdown site is intentionally provided to visually confirm that the dielectric breakdown has occurred. The gist is to mount an element on a substrate, and flow the substrate on which the electrostatic discharge detecting element is mounted to the manufacturing process to identify a partial process in which the dielectric breakdown has occurred.

  According to this configuration, when dielectric breakdown due to electrostatic discharge occurs in the electronic device in a manufacturing process in which the electronic device is mounted on the substrate and the electronic device is manufactured, this can be detected with high accuracy. Thereby, in the manufacturing process, the partial process in which the dielectric breakdown has occurred in the electronic device can be specified with high accuracy, and further, in the partial process, a measure for suppressing the occurrence of electrostatic discharge can be taken. In addition, if dielectric breakdown occurs in the electrostatic discharge detection element during the same manufacturing process, even if the product is a standard-compliant product, the electronic device obtained in the same manufacturing process is considered to have been damaged to some extent by electrostatic discharge. Therefore, it is possible to take measures such as shipment suspension.

  According to a sixth aspect of the present invention, in the electrostatic discharge detection method according to the fifth aspect, the electrostatic discharge detection element is classified into layers based on a dielectric breakdown strength range of the dielectric breakdown site, and the plurality of hierarchically classified The gist of the invention is to mount a kind of electrostatic discharge detecting element on a substrate and flow it through the manufacturing process.

  According to this configuration, a plurality of types of electrostatic discharge detection elements that are hierarchically classified based on the breakdown strength range of the dielectric breakdown site are passed through the manufacturing process of the electronic device, so that the detection element is insulated in any of the partial processes. If the breakdown state is statistically observed when breakdown occurs, it can be used as a criterion for determining the degree of contamination due to static electricity in the partial process. As a result, it is possible to take measures to suppress the occurrence of electrostatic discharge according to the degree of contamination of each partial process.

  In addition, when multiple types of electrostatic discharge detection elements classified hierarchically based on the dielectric breakdown strength range of the dielectric breakdown site are passed through the manufacturing process of electronic equipment, dielectric breakdown occurs in the electronic device in any of the partial processes Furthermore, if the dielectric breakdown state of each detection element is statistically observed, it can be used as a criterion for determining the dielectric strength of the electronic device (the level of dielectric strength of the electronic device can be quantified).

  Further, in one partial process, when an electrostatic discharge detecting element having a predetermined breakdown strength has a dielectric breakdown, the dielectric breakdown strength is exceeded (by increasing the gap width between wiring patterns or resistors, or by conducting If the electronic device is designed so as to increase the thickness of the insulating film between the bodies, it can be expected (guaranteeed) with high accuracy that no defective product will be generated from the electronic device obtained in the manufacturing process.

  ADVANTAGE OF THE INVENTION According to this invention, when the dielectric breakdown by electrostatic discharge generate | occur | produces in the electronic device mounted on the board | substrate, it becomes possible to provide the electrostatic discharge detection element and the electrostatic discharge detection method which can detect that to high accuracy. .

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. The electrostatic discharge detecting element according to each embodiment shown below is manufactured by mounting an IC chip as an electronic device on a printed circuit board (printed wiring board) to manufacture an automotive device (electronic device) such as an engine control unit. This is to detect that dielectric breakdown due to electrostatic discharge has occurred between the metal wiring pattern of the IC chip or resistors such as P-type and N-type diffusion layers in the process.

<First Embodiment>
The electrostatic discharge detection element 1 of this embodiment is applied to a manufacturing process in which an IC chip that is expected to cause electrostatic discharge in an Al (aluminum) metal wiring pattern is mounted on a printed circuit board to manufacture an engine control unit. Is. Here, the Al metal wiring pattern of the IC chip has a folded structure.

  Referring to FIG. 1 (a), in this electrostatic discharge detecting element 1, on the circuit board 2 so that the same problem occurs in the situation where dielectric breakdown due to electrostatic discharge occurs in the Al metal wiring pattern of the IC chip. An Al metal wiring pattern 1a having a folded structure is formed on the surface, and dielectric breakdown due to electrostatic discharge is likely to occur in the Al metal wiring pattern 1a, and it can be confirmed using equipment that the dielectric breakdown has occurred. Intentional breakdown sites are intentionally provided.

  Specifically, referring to FIG. 1B, the dielectric breakdown part is provided in a part where the Al metal wiring patterns 1a are separated by a predetermined gap width d1 [nm]. In the eight (plurality) of electrostatic discharge detection elements 1,... Used in the present embodiment, the gap width d1 [nm] is set to a constant value. Here, the gap width d1 [nm] is determined according to the pattern rule of the IC chip so as to match the dielectric breakdown strength of the IC chip.

  The electrostatic discharge detection elements 1,... Are respectively similar to the IC chip in order to detect, for example, when dielectric breakdown due to electrostatic discharge occurs in an IC chip mounted on a printed circuit board. One by one is mounted on each printed circuit board. Then, the eight printed circuit boards (electronic circuit boards) obtained in this way are passed from the start point to the manufacturing process of the engine control unit consisting of the following eight (plural) partial processes S1 to S8, Each time when the partial steps S1 to S8 are completed, one piece is sampled, and it is confirmed by using an apparatus whether or not dielectric breakdown due to electrostatic discharge has occurred in the dielectric breakdown portion of each electrostatic discharge detection element 1.

  As shown in FIG. 2, first, in an IC chip mounting step S1, an IC chip is mounted on a wiring portion to which solder is attached on a printed board. In the IC chip reflow processing step S2, solder is dissolved by reflow processing to complete the soldering of the IC chip to the printed board, and the mounted IC chip is mounted on the printed board.

  After mounting the IC chip, in the appearance inspection / repair step S3, the soldering defect part on the printed circuit board is mainly found and the part is repaired. Thereafter, in the electrical component mounting step S4, electrical components such as a connector and a relay circuit are mounted on the wiring portion to which the solder on the printed board is attached. Subsequently, in the electrical component reflow processing step S5, the solder is dissolved by reflow processing to complete the soldering of the electrical component, and the mounted electrical component is mounted on the printed circuit board.

  After mounting the electrical components, in the appearance inspection / repair step S6, the soldering defect part on the printed circuit board is mainly found and the part is repaired. Thereafter, in the printed circuit board error / missing part inspection step S7, the printed circuit board obtained by completing the mounting of the IC chip / electrical component on the printed circuit board is inspected for an incorrect or missing part of the chip / part. .

  Then, a case or cover is attached to the printed circuit board to complete the engine control unit, and in the electronic device function inspection step S8, a function inspection of the control unit is performed using a dedicated inspection device.

  When each of the partial processes S1 to S8 is finished, the printed circuit board on which the electrostatic discharge detecting element 1 of this embodiment is mounted is sampled one by one, and the insulation breakdown portion of each detecting element 1 is insulated by electrostatic discharge. Observe with the instrument whether or not destruction occurred.

  Specifically, as shown in FIG. 3 (a), a printed circuit board 20 (printed circuit board) on which the electrostatic discharge detecting element 1 is mounted in an off-line state sampled from the manufacturing process is inspected in an insulation resistance test apparatus. The insulation resistance tester 5 (apparatus) is connected to the dielectric breakdown part of the detection element 1 via the probe 3 and the cable 4 and the dielectric breakdown state of the dielectric breakdown part is observed.

  Specifically, as shown in FIG. 3B, the gap width d1 between the Al metal wiring patterns 1a and 1a of the electrostatic discharge detecting element 1 mounted on the circuit wiring 20a on the printed board 20 via the lead wire 1b. The probe 3 is connected to a dielectric breakdown site (see FIG. 1B) separated by [nm], and further connected to the insulation resistance tester 5 via the cable 4, and the insulation resistance of the dielectric breakdown site Measure the value [MΩ].

  As a result, the electrostatic discharge sampled together with the printed circuit board 20 after the end of any of the partial steps S1 to S8, for example, after the electrical component mounting step S4 and the printed circuit board error / missing part inspection step S7. When the insulation resistance value of the detection element 1 is lower than a predetermined value (for example, 10 [MΩ]), dielectric breakdown occurs in the electrostatic discharge detection element 1 due to electrostatic discharge in the partial processes S4 and S7. It is confirmed that it was.

According to the electrostatic discharge detection element 1 or the electrostatic discharge detection method of the present embodiment, the following operations and effects can be obtained.
(1) In the electrostatic discharge detecting element 1, an Al metal wiring pattern is a dielectric breakdown site that is likely to cause dielectric breakdown due to electrostatic discharge and that can be confirmed by using the insulation resistance tester 5. 1a is set at a site separated by a predetermined gap width d1 [nm] that matches the dielectric breakdown strength of the IC chip. Then, it is possible to confirm that dielectric breakdown has occurred between the Al metal wiring patterns 1a by observing using the insulation resistance tester 5. For this reason, in the manufacturing process of manufacturing the engine control unit, if dielectric breakdown occurs due to electrostatic discharge in the IC chip, it can be detected with high accuracy by practical and rational means.

  (2) In the electrostatic discharge detecting element 1, when dielectric breakdown occurs due to electrostatic discharge with a predetermined gap width d1 [nm] set between the Al metal wiring patterns 1a, an IC chip having the same dielectric breakdown resistance can be used. It becomes possible to estimate with high accuracy that dielectric breakdown may occur. Therefore, if the IC chip is designed so that the gap width between the Al metal wiring patterns 1a is appropriately longer than d1 [nm] so as to exceed the dielectric breakdown strength, the engine control unit obtained in the same manufacturing process can be used. It can be expected (guaranteeed) with high accuracy that no defective product is generated.

  (3) Deliberately lowering the electrostatic breakdown strength of the electrostatic discharge detection element 1 (in other words, making it easy to break down due to electrostatic discharge), that is, appropriately shortening the gap width between the Al metal wiring patterns 1a, If this is applied to the manufacturing process and dielectric breakdown does not occur in that state, it can be expected with high accuracy that dielectric breakdown will not occur even with an IC chip having the same level of electrostatic breakdown resistance. As a result, the reliability of the engine control unit manufacturing process is improved, and the reliability of the engine control unit manufactured through the manufacturing process is improved.

  (4) When a failure occurs in the engine control unit actually manufactured by the same manufacturing process, it can be estimated with high accuracy that the failure is caused by electrostatic discharge, and the location where the electrostatic discharge has occurred is It becomes possible to specify the partial process S4 or S7 with high accuracy. Thereby, in the said partial process S4 or S7, the process which suppresses generation | occurrence | production of electrostatic discharges, such as the worker who engages in the process, and antistatic and removal of charge of a production facility, can be taken now.

  (5) On the other hand, even when no failure has occurred in the engine control unit, in the partial processes S4 and S7, it is highly likely that electrostatic discharge has occurred in the IC chip and dielectric breakdown is likely to occur. Can be estimated. As a result, even if the engine control unit obtained in the same manufacturing process is a product that meets the standards, it can be assumed that it has been damaged to some extent by electrostatic discharge, and measures such as shipment stoppage can be taken. It becomes.

Second Embodiment
The electrostatic discharge detecting element 1 ′ of the present embodiment is manufactured by mounting an IC chip on a printed circuit board on which an electrostatic discharge is assumed to occur in a resistor composed of a P-type (N-type) diffusion layer, and manufacturing an engine control unit. It is applied to the manufacturing process.

  Referring to FIG. 4 (a), in this electrostatic discharge detecting element 1 ', the circuit board (N-type) is used so that a similar problem occurs in a situation where dielectric breakdown occurs due to electrostatic discharge in the resistor of the IC chip. A resistor 1a ′ composed of a P-type (N-type) diffusion layer is formed on the (P-type) silicon substrate 2 and the dielectric breakdown due to electrostatic discharge is likely to occur in the resistor 1a ′. A dielectric breakdown site where the fact that the dielectric breakdown has occurred can be confirmed using equipment is intentionally provided.

  Specifically, referring to FIG. 4 (b), the dielectric breakdown site has a sharp tip at a pair of resistors 1a 'and 1a' made of a P-type (N-type) diffusion layer, The protrusions 1t and 1t are provided to be opposed to each other with a gap width d2 [nm]. Here, the three types (plural types) of electrostatic discharge detection elements 1 ′ [1] to 1 ′ [3] used in the present embodiment are within the range of the gap width d2 [nm], that is, the detection element 1 ′. Hierarchical classification is based on the dielectric breakdown strength range of dielectric breakdown sites. Specifically, it is as shown in Table 1 below so as to approximate the dielectric breakdown strength of the IC chip.

そして、前記静電気放電検出素子１´，…は、例えば、プリント基板上に装着されたＩＣチップに静電気放電による絶縁破壊が発生した場合に、その旨を検出等すべく、前記階層分類に基づき、ギャップ幅ｄ２［ｎｍ］の範囲が異なるものがそれぞれ３種（３個）ずつ、合計８枚の各プリント基板上に実装される。そして、こうして得られた８枚のプリント回路板が、図３に示す製造工程と同様に部分工程Ｓ１〜Ｓ８からなるエンジンの制御ユニットの製造工程にその開始時点から流され、各部分工程Ｓ１〜Ｓ８が終了する都度、１枚ずつサンプリングされ、各プリント基板上の３種の静電気放電検出素子１´［１］〜１´［３］の絶縁破壊部位に静電気放電による絶縁破壊が発生したか否かが第１実施形態と同様に絶縁抵抗試験器５を用いて確認される。

And, for example, when dielectric breakdown due to electrostatic discharge occurs in an IC chip mounted on a printed circuit board, the electrostatic discharge detection elements 1 ′,... Those having different gap widths d2 [nm] are mounted on a total of eight printed boards, each of three types (three). Then, the eight printed circuit boards obtained in this way are passed from the start point to the manufacturing process of the engine control unit consisting of the partial processes S1 to S8 as in the manufacturing process shown in FIG. Each time S8 is finished, one sheet is sampled, and whether or not dielectric breakdown due to electrostatic discharge has occurred in the dielectric breakdown sites of the three types of electrostatic discharge detection elements 1 ′ [1] to 1 ′ [3] on each printed circuit board. Is confirmed using the insulation resistance tester 5 as in the first embodiment.

  As a result, the electrostatic discharge detection elements 1 ′ [1] and 1 ′ [2 sampled together with the printed circuit board 20 after the end of any of the partial steps S1 to S8, for example, after the end of the electrical component reflow processing step S5. ] Is lower than a predetermined value (for example, 10 [MΩ]), it corresponds to the gap width d2 [nm] (= 100 to 1000 [nm]) in the partial step S5. It is confirmed that the dielectric breakdown has occurred in the electrostatic discharge detecting element 1 ′ (that is, the elements [1] and [2]) having the dielectric breakdown strength or less due to electrostatic discharge.

According to the electrostatic discharge detection element 1 ′ or the electrostatic discharge detection method of the present embodiment, the following operations / effects can be obtained in addition to the operations / effects obtained in the first embodiment.
(6) A portion where dielectric breakdown due to electrostatic discharge has occurred in the detection element 1 ′ by statistical observation using three types of electrostatic discharge detection elements 1 ′,. It can be used as a criterion for determining the degree of contamination due to static electricity in step S5. As a result, it is possible to take measures to suppress the occurrence of electrostatic discharge according to the degree of contamination in the partial step S5.

  (7) The three types of electrostatic discharge detection elements 1 ′ [1] to 1 ′ [3] classified hierarchically based on the dielectric breakdown strength range of the dielectric breakdown sites are flowed through the manufacturing process of the engine control unit, and the part If the breakdown state of each detection element 1 ′ is statistically observed when breakdown occurs in the IC chip in any of the steps, it can be used as a criterion for determining the breakdown strength of the IC chip ( The level of dielectric strength of IC chips can be quantified).

  (8) Further, when a dielectric breakdown occurs in the electrostatic discharge detecting elements 1 ′ [1] and 1 ′ [2] having a predetermined breakdown strength in one partial step S5 as in the present embodiment, the insulation is performed. For example, an IC chip having a breakdown strength equivalent to that of the electrostatic discharge detection element 1 ′ in which the gap width d2 [nm] between the resistors 1a ′ and 1a ′ is appropriately longer than 1000 [nm] so as to exceed the breakdown strength. Can be expected (guaranteed) with high accuracy that no defective product will be generated from the engine control unit obtained in the same manufacturing process.

<Third Embodiment>
In the electrostatic discharge detection element 10 of the present embodiment, an IC chip on which an electrostatic discharge is assumed to occur in an MR element (ferromagnetic magnetoresistive element) as a conductor is mounted on a printed circuit board, and control of an automobile switch is performed. The present invention is applied to a manufacturing process for manufacturing a unit.

Referring to FIG. 5 (a), in this electrostatic discharge detecting element 10, the silicon substrate (semiconductor) 11 is arranged so that a similar problem occurs in a situation where dielectric breakdown due to electrostatic discharge occurs in the MR element of the IC chip. The MR elements 10a and 10a are formed on the silicon oxide film (SiO ₂ ) 12 on the top, and the MR elements 10a and 10a are susceptible to dielectric breakdown due to electrostatic discharge, and the dielectric breakdown occurs. A dielectric breakdown site that can be confirmed using equipment is intentionally provided. In FIG. 5A, the silicon oxide film (SiO ₂ ) 12 and the MR elements 10 a and 10 a are further covered with an interlayer insulating film (SiO) 13 and a passivation film (SiN) 14.

  Specifically, referring to FIG. 5B, the dielectric breakdown site is a silicon oxide film 12 having a predetermined uniform film thickness d3 [nm] between the MR elements 10a, 10a and the silicon substrate 11. It is provided in an insulated part. In the eight (plural) electrostatic discharge detecting elements 10 used in the present embodiment, the film thickness d3 [nm] is set to a constant value. Here, the film thickness d3 [nm] is preferably in the range of 500 [nm] or more and 1000 [nm] or less, for example, so as to match the dielectric breakdown strength of the IC chip.

  The electrostatic discharge detection elements 10,... Are respectively the same as the IC chip in order to detect, for example, when an insulation breakdown due to electrostatic discharge occurs in an IC chip mounted on a printed circuit board. One by one is mounted on each printed circuit board. Then, the eight printed circuit boards obtained in this way are passed from the start point to the manufacturing process of the control unit of the automotive switch consisting of the partial processes S1 to S8 in the same manner as the manufacturing process shown in FIG. Each time S1 to S8 are completed, one sheet is sampled, and whether or not dielectric breakdown due to electrostatic discharge has occurred in the dielectric breakdown portion of each electrostatic discharge detection element 10 is the same as in the first and second embodiments. This is confirmed using the vessel 5.

  As a result, the insulation resistance value of the electrostatic discharge detection element 10 sampled together with the printed circuit board 20 after the end of any of the partial steps S1 to S8, for example, after the appearance inspection / repair step S6 after mounting the electrical components. Is lower than a predetermined value (for example, 10 [MΩ]), it is confirmed in the partial step S6 that dielectric breakdown has occurred in the electrostatic discharge detection element 10 due to electrostatic discharge.

According to the electrostatic discharge detection element 10 or the electrostatic discharge detection method of the present embodiment, the following operations and effects can be obtained.
(9) Dielectric breakdown due to electrostatic discharge is likely to occur, and the dielectric breakdown site where the dielectric breakdown can be confirmed using the insulation resistance tester 5 is the MR element 10a, 10a and the silicon substrate 11 are set to be insulated by a silicon oxide film 12 having a predetermined uniform film thickness d3 [nm] that matches the dielectric breakdown strength of the IC chip. It is possible to confirm that dielectric breakdown has occurred in the silicon oxide film 12 by observing using the insulation resistance tester 5. For this reason, when dielectric breakdown due to electrostatic discharge occurs in the IC chip in the manufacturing process of manufacturing the control unit for the automotive switch, it can be detected with high accuracy by practical and rational means.

  (10) In the electrostatic discharge detection element 10, when dielectric breakdown due to electrostatic discharge occurs at a predetermined film thickness d3 [nm] set in the silicon oxide film 12 between the MR element 10a and the silicon substrate 11, the same level It becomes possible to estimate with high accuracy that dielectric breakdown can occur even in an IC chip having dielectric strength. For this reason, if the IC chip is designed so that the thickness of the silicon oxide film 12 is appropriately larger than d3 [nm] so as to exceed the dielectric breakdown strength, the control unit of the automotive switch obtained in the same manufacturing process can be used. It can be expected (guaranteeed) with high accuracy that no defective product is generated.

  (11) The electrostatic breakdown resistance of the electrostatic discharge detection element 10 is intentionally lowered, that is, the thickness of the silicon oxide film 12 between the MR elements 10a, 10a and the silicon substrate 11 is appropriately reduced, and this is passed to the manufacturing process. If dielectric breakdown does not occur in that state, it can be expected with high accuracy that dielectric breakdown does not occur even with an IC chip having the same level of electrostatic breakdown strength. As a result, the reliability of the automotive switch control unit in the manufacturing process is improved, and the reliability of the automotive switch control unit manufactured through the manufacturing process is improved in quality.

The above embodiment may be modified as follows.
In each of the above embodiments, it can be confirmed by the insulation resistance tester 5 as a device that dielectric breakdown has occurred due to electrostatic discharge at the dielectric breakdown site. However, the technical idea of the present invention is not limited to this, and a visual confirmation means, for example, a dielectric breakdown part of the electrostatic discharge detection element 1 (1 ′, 10), that is, an Al metal wiring pattern 1a (resistor 1a ′). For example, an LED (Light Emitting Diode) is connected between the gaps (between the MR element 10a and the silicon substrate 11), and an IC chip is mounted in the manufacturing process of each electronic device. Light emission that occurs when dielectric breakdown occurs due to electrostatic discharge may be observed directly with the naked eye in an in-line state that flows along with a printed circuit board on which is mounted.

  In each of the above embodiments, it can be confirmed by the insulation resistance tester 5 as a device that dielectric breakdown has occurred due to electrostatic discharge at the dielectric breakdown site. However, the present invention is not limited to this, and the confirmation means by the device is to sample the electrostatic discharge detection element 1 (1 ′, 10) from the manufacturing process at a predetermined timing, and observe it in an off-line state using a microscope. Also good.

  In each of the above embodiments, the electrostatic discharge detection elements 1, 1 ', 10 are sampled each time the partial steps S1 to S8 of the manufacturing process of the electronic device such as the engine control unit are completed, and the insulation resistance of the dielectric breakdown site The value [MΩ] is measured to observe the state of dielectric breakdown of the detection elements 1, 1 ′, and 10, and as a result, the partial process where the dielectric breakdown actually occurred in the IC chip or the dielectric breakdown can occur in the IC chip A high-performance partial process was specified. However, the present invention is not limited to this, and each time the partial steps S1 to S8 are finished, the insulation resistance value [MΩ] of the dielectric breakdown site is measured. The printed circuit board or the printed circuit board may be poured into the partial process, and the manufacture of the electronic device using the printed circuit board or the like may be continued. That is, the electrostatic discharge detection elements 1, 1 ', 10 can be used for process line check.

  In each of the above embodiments, the printed circuit board or the printed circuit board on which the electrostatic discharge detection elements 1, 1 ′, 10 are mounted is flown through the manufacturing process of the electronic device, and the dielectric breakdown due to electrostatic discharge is caused on the IC chip mounted on the printed circuit board 20 When it occurred, it was used for the purpose of specifying which of the partial processes constituting the manufacturing process caused the dielectric breakdown. However, the present invention is not limited to this, and the electrostatic discharge detection elements 1, 1 'and 10 are mounted on the same printed circuit board together with an electronic device such as an IC chip in a printed circuit board or an electronic device as a product and distributed to the market. Is also possible. Here, the electronic device refers to a device including an IC chip that exhibits a predetermined function and an input / output device that exchanges signals with the outside. For example, the automotive device exemplified in the above embodiment, Various general-purpose communication devices are listed. As a result, when the printed circuit board or the electronic device is distributed in the market, when the dielectric breakdown occurs in the detection elements 1, 1 ', 10, the defective printed circuit board or the electronic device is caused by electrostatic discharge. The origin can be specified with high accuracy, and the defective product can be selectively excluded from the distribution route. Further, when a defective product is generated for some reason in the distribution route of printed circuit boards or electronic devices as products, it can be specified with high accuracy whether the cause is due to electrostatic discharge. In other words, the printed circuit board and the electronic device can exhibit the same functions as the impact sensor mounted to identify a failure due to an impact during transportation or the water detection sensor mounted to identify a failure due to water wetting. it can.

  In the first embodiment, an Al metal wiring pattern 1a having a folded structure is used for the electrostatic discharge detection element 1, but instead of such an Al metal wiring pattern 1a, a P-type as used in the second embodiment is used. The resistor 1a ′ made of an (N-type) diffusion layer may be used as a folded structure.

  In the second embodiment, the electrostatic discharge detection element 1 is made of the P-type (N-type) diffusion layer, and the projecting portions 1t and 1t facing each other so as to have a predetermined gap width d2 [nm] are provided. Although the resistor 1a ′ having the same structure is used, the Al metal wiring pattern 1a used in the first embodiment is replaced with a similar protruding portion instead of the resistor 1a ′ formed of the P-type (N-type) diffusion layer. May be used to have

  In the second embodiment, the manufacturing process using an IC chip in which electrostatic discharge is assumed to occur in the resistor 1a ′ composed of a P-type (N-type) diffusion layer is targeted, but the present invention is not limited thereto. A manufacturing process using an IC chip in which electrostatic discharge is assumed to occur in a resistor made of Ni—Co, Ni—Fe, or polycrystalline silicon can also be targeted.

  In the second embodiment, a plurality of types of electrostatic discharge detection elements 1 ′,... Hierarchically classified based on the dielectric breakdown strength range of the dielectric breakdown sites are used, and these are passed to the manufacturing process of the electronic device, and statistical observation is performed. The detection element 1 ′ was used as a criterion for determining the degree of contamination due to static electricity in a partial process where dielectric breakdown occurred due to electrostatic discharge. However, the present invention is not limited to this, and the electrostatic discharge detection element 1 used in the first embodiment and the electrostatic discharge detection element 10 used in the third embodiment are classified hierarchically based on the dielectric breakdown strength range of those dielectric breakdown sites. Such statistical observation may be used as a criterion for determining the degree of contamination due to static electricity in a partial process.

It is a figure which shows the structure of the electrostatic discharge detection element which concerns on 1st Embodiment of this invention, (a) is the perspective view, (b) is the enlarged view of the dielectric breakdown part. The manufacturing process figure which shows an example of the manufacturing process of an electronic device. It is a figure which shows the state which is measuring the insulation resistance value of the electrostatic discharge detection element which concerns on 1st Embodiment of this invention with an insulation resistance tester, (a) is the whole figure, (b) is a principal part enlarged view. . It is a figure which shows the structure of the electrostatic discharge detection element which concerns on 2nd Embodiment of this invention, (a) is the perspective view, (b) is the enlarged view of the dielectric breakdown part. It is a figure which shows the structure of the electrostatic discharge detection element which concerns on 3rd Embodiment of this invention, (a) is the sectional drawing, (b) is the enlarged view of the dielectric breakdown site | part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1, 1 ', 10 ... Electrostatic discharge detection element, 1a ... Al metal wiring pattern, 1a' ... Resistor which consists of a P-type (N-type) diffusion layer, 1t ... Projection part, 2 ... Circuit board, 11 ... Silicon substrate, 20 ... Printed circuit board, d1, d2 ... Gap width, d3 ... Film thickness (of silicon oxide film), S1-S8 ... Partial process.

Claims (6)

An electrostatic discharge detection element for detecting the occurrence of dielectric breakdown due to electrostatic discharge in an electronic device mounted on a substrate,
An electrostatic discharge detecting element characterized in that a dielectric breakdown part is intentionally provided, and a dielectric breakdown part where the dielectric breakdown can be visually confirmed or confirmed using an instrument is provided. The electrostatic discharge detecting element according to claim 1,
The insulation breakdown part is a part where a wiring pattern or resistor provided in the detection element is separated by a predetermined gap width, or a conductor or semiconductor provided in the detection element is insulated by an insulating film having a predetermined thickness. Electrostatic discharge detection that is set at the site where it is possible to confirm that the dielectric breakdown has occurred by observing visually that the wiring pattern or the resistor, or between the conductors are conductive element. An electronic circuit board formed by mounting an electronic device on a substrate,
An electronic circuit board, wherein the electrostatic discharge detection element according to claim 1 or 2 is mounted on the same substrate together with the electronic device. An electronic device including an electronic device that performs a predetermined function and an input / output device that exchanges signals with the outside,
An electronic device comprising the electronic circuit board according to claim 3. An electrostatic discharge detection method for detecting that dielectric breakdown due to electrostatic discharge has occurred in an electronic device in a manufacturing process of mounting an electronic device on a substrate and manufacturing an electronic device,
The manufacturing process comprises a plurality of partial processes,
The dielectric breakdown is easily generated, and an electrostatic discharge detecting element intentionally provided with a dielectric breakdown part that can be confirmed visually or by using a device that the dielectric breakdown has occurred is mounted on a substrate,
An electrostatic discharge detection method for specifying a partial process in which the dielectric breakdown has occurred by flowing a substrate mounted with the electrostatic discharge detection element to the manufacturing process. In the electrostatic discharge detection method according to claim 5,
The electrostatic discharge detection element is hierarchically classified based on a dielectric breakdown tolerance range of the dielectric breakdown site, and the electrostatic discharge detection element that is mounted on a substrate and the plurality of types of electrostatic discharge detection elements classified in the hierarchy are flowed to the manufacturing process. Method.

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