WO2019026213A1 - Soft error inspection method, soft error inspection device, and soft error inspection system - Google Patents

Soft error inspection method, soft error inspection device, and soft error inspection system Download PDF

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WO2019026213A1
WO2019026213A1 PCT/JP2017/028111 JP2017028111W WO2019026213A1 WO 2019026213 A1 WO2019026213 A1 WO 2019026213A1 JP 2017028111 W JP2017028111 W JP 2017028111W WO 2019026213 A1 WO2019026213 A1 WO 2019026213A1
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semiconductor device
soft error
error inspection
thickness
wavelength
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PCT/JP2017/028111
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French (fr)
Japanese (ja)
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添田　武志
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富士通株式会社
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Priority to PCT/JP2017/028111 priority Critical patent/WO2019026213A1/en
Priority to JP2019533802A priority patent/JP6822572B2/en
Publication of WO2019026213A1 publication Critical patent/WO2019026213A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/26—Testing of individual semiconductor devices

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  • the present invention relates to a soft error inspection method, a soft error inspection apparatus and a soft error inspection system.
  • test using an accelerator can be further divided into a method of irradiating neutrons or ions to the entire surface of the LSI chip and a method of locally irradiating collectable electrons or laser light.
  • the laser evaluation method can be realized with small-scale equipment because it does not need to be vacuum, and is excellent in that a specific memory area can be individually evaluated.
  • charges are generated through a process of two-photon absorption using laser light of a wavelength in the infrared region (for example, 1500 nm).
  • transistors and the like are formed on the surface side of a semiconductor device such as an LSI chip, and wires and the like connected to these transistors and the like are formed of a metal material.
  • the inspection is performed by irradiating a laser beam. Therefore, in order to irradiate the portion where the transistor is formed with the laser light with a predetermined power, the distance from the back surface to the portion where the transistor on the front side is formed, that is, the thickness of the semiconductor device is predetermined. It is necessary to polish the back surface of the silicon substrate so as to have a thickness.
  • An explanatory view (1) of back surface polishing of a semiconductor device An explanatory view (2) of the back surface polishing of a semiconductor device Correlation diagram of wavelength of light irradiated to silicon and penetration depth Structure diagram of the soft error inspection device in the present embodiment Flow chart of soft error inspection method in the present embodiment Explanation of wavelength control condition table used in the present embodiment Explanatory drawing (1) of the soft error inspection method in this embodiment Explanatory drawing (2) of the soft error inspection method in this embodiment
  • the distance from the back surface 10b of the silicon substrate of the semiconductor device 10 to the transistor forming layer 11 is the same, that is, the back surface 10b and the front surface of the silicon substrate of the semiconductor device 10. It is necessary to polish so that it is parallel to 10a. However, such polishing is extremely difficult, and when the polishing is actually performed, the back surface 10b of the silicon substrate of the semiconductor device 10 is inclined with respect to the surface 10a as shown in FIG. 1 (b). Such a tendency becomes even more pronounced when the person who is not accustomed to polishing performs.
  • the back surface 10b of the silicon substrate of the semiconductor device 10 there is local polishing such as dimple polishing for forming the dimple surface 10c on the back surface 10b of the silicon substrate of the semiconductor device 10 other than the above.
  • dimple polishing although it is necessary to form the dimple surface 10 c accurately on the back surface 10 b at the desired position to be inspected, the dimple surface 10 c exactly on the back surface 10 b of the silicon substrate of the semiconductor device 10 at the desired position. It is extremely difficult to form Further, in dimple polishing, the thickness of the dimple surface 10c differs from part to part.
  • the wavelength of infrared light that causes two-photon absorption is 1.1 ⁇ m to 2.1 ⁇ m, but the transmittance in silicon depends on the wavelength (energy), When the wavelength of infrared light to be irradiated changes, the transmittance also changes.
  • FIG. 3 shows the relationship between the wavelength of the light to be irradiated and the penetration depth in silicon. As shown in FIG. 3, when the wavelength of light irradiated to silicon changes, the penetration depth in silicon also changes.
  • FIG. 3 is based on the description of Non-Patent Document 1, and the penetration depth can be defined from absorbance measurement. Taking the ratio of incident light to outgoing light to a known wavelength and sample thickness, the absorbance is 1 when the light is completely absorbed, the transmittance is 0, and the thickness is plotted in FIG. FIG. 3 can also be referred to as a depth where light can not penetrate further.
  • the value of penetration depth also changes in accordance with the concentration of the doped impurity element.
  • the transmittance of infrared light having a wavelength of 1.1 ⁇ m to 1.2 ⁇ m is the highest, and the concentration of the doped impurity is high.
  • N 2.4 ⁇ 10 19 cm ⁇ 3 is obtained by doping silicon with an N-type impurity element at a concentration of 2.4 ⁇ 10 19 cm ⁇ 3 .
  • the thickness of the region to be inspected of the silicon substrate can be measured using an interference microscope such as a confocal microscope or an optical interferometer.
  • the thickness of the silicon substrate of the semiconductor device is measured for each part of the area to be subjected to the soft error inspection, and laser light is irradiated while changing the wavelength based on the measured thickness. Check for soft errors. This makes it possible to check soft errors accurately and quickly.
  • the semiconductor device 10 which is a sample to be inspected is an LSI chip or the like, and the semiconductor device 10 is installed on the scanning stage 20 and moved in two dimensions, ie, the X axis direction and the Y axis direction by the scanning stage 20 Can.
  • the scanning stage 20 is controlled by the scanning control unit 21.
  • the semiconductor device 10 is as shown in FIG. 1 (a) or FIG. 1 (b).
  • the irradiation source 30 emits a laser beam irradiated to the semiconductor device 10, is a variable-wavelength laser capable of changing the wavelength, and is controlled by the irradiation control unit 31.
  • the irradiation control unit 31 controls the irradiation control unit 31.
  • the wavelength of the laser light emitted from the irradiation source 30 is about approximately because the wavelength region where two-photon absorption occurs in silicon is 1100 nm to 2100 nm. It is 1500 nm.
  • the substrate thickness measurement unit 40 is an interference microscope such as a confocal microscope or an optical interferometer, and is controlled by the substrate thickness measurement control unit 41.
  • the measuring device 50 is a tester or the like, is connected to the terminal of the semiconductor device 10, and can measure a change in information stored in the semiconductor device 10.
  • the control unit 60 performs control of the entire soft error inspection apparatus according to the present embodiment and information processing operation related to the soft error inspection method, and the scan control unit 21, the irradiation control unit 31, the substrate thickness measurement control unit 41, and the measurement The vessel 50 and the like are connected.
  • the information processing unit 61 is connected to a storage unit 62 for storing information, a display unit 63 for displaying necessary information, and an input unit 64 for inputting information to the information processing unit 61.
  • the control of the control unit 60 is a soft error inspection system capable of executing the soft error inspection method described below.
  • the semiconductor device 10 to be inspected in the soft error inspection method in the present embodiment is a static random access memory (SRAM), a flash memory, a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC) or the like.
  • the soft error inspection method according to the present embodiment is performed based on the control of the control unit 60. In the present embodiment, it is assumed that the relationship between the wavelength of infrared light irradiated to silicon and the transmission depth is measured in advance or obtained from literature or the like, and this information is stored in the storage unit 62. Shall be stored in
  • step 102 the back surface of the silicon substrate in the semiconductor device 10 to be inspected for soft errors is polished.
  • the silicon substrate of the semiconductor device 10 is polished so as to have a thickness of about 50 ⁇ m. With this thickness, no cracking or damage occurs in the silicon substrate.
  • the thickness of the silicon substrate after polishing may have variations or the like.
  • step 104 the thickness of a portion of the semiconductor device 10 in which the region to be inspected for soft errors is measured by the substrate thickness measurement unit 40, and the process proceeds to step 106 (S106).
  • step 106 whether or not the measurement of the thickness for each portion of the area to be inspected for soft errors in the semiconductor device 10 is completed, ie, the scan for measuring the thickness for each portion of the area to be inspected To determine if the If scanning for measuring the thickness of each part of the area to be inspected for soft errors is completed, the process proceeds to step 110, and the thickness for each part of the area to be inspected for soft errors is measured. If the scanning for the image has not been completed, the process proceeds to step 108.
  • step 112 the thickness of the semiconductor device 10 measured in steps 104 to 108 so that the irradiated transmittance becomes uniform based on the value of the impurity concentration of the semiconductor device 10 input. Extract the wavelength of infrared light corresponding to.
  • a wavelength control condition table is created based on the wavelength extracted in step 112.
  • the wavelength control condition table is, for example, as shown in FIG. 6, in which the wavelengths of infrared light corresponding to the thickness of the semiconductor device 10 are two-dimensionally arranged in M rows and N columns, and the storage unit It is stored in 62.
  • step 116 the semiconductor device 10 to be inspected is irradiated with the laser light for a predetermined time while changing the wavelength of the laser light based on the wavelength control condition table shown in FIG. Check for soft errors.
  • a predetermined position of the semiconductor device 10 is irradiated with laser light for a predetermined time, and time-series data of bit information of the position where the laser light is irradiated is measured and stored. It stores in part 62 grade.
  • the temporal change of information is measured and stored in the storage unit 62 or the like.
  • FIG. 8 shows time-series data of bit information of a position where the laser light detected by the measuring device 50 is irradiated.
  • FIG. 8A shows that bit information is inverted from 0 to 1 when time t1 has elapsed from the start of laser beam irradiation.
  • FIG. 8 (b) at the time from the start of laser beam irradiation, the time t 2 has passed, showing that bit information is reversed to 0 ⁇ 1.
  • the soft error inspection method in the present embodiment even if the thickness of the semiconductor device 10 is not uniform, accurate inspection can be performed in the area to be inspected for soft errors.
  • Reference Signs List 10 semiconductor device 20 scan stage 21 scan control unit 30 irradiation source 31 irradiation control unit 40 substrate thickness measurement unit 41 substrate thickness measurement control unit 50 measurement unit 60 control unit 61 information processing unit 62 storage unit 63 display unit 64 input unit

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Testing Or Measuring Of Semiconductors Or The Like (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Testing Of Individual Semiconductor Devices (AREA)

Abstract

This soft error inspection method for a semiconductor device is characterized by comprising: a step for polishing the back surface of the semiconductor device, thereafter, a step for measuring the thicknesses of a plurality of parts of a soft error inspection area of the semiconductor device, a step for irradiating laser light of wavelengths corresponding to the thicknesses of the semiconductor device onto the back surface of the semiconductor device, and a step for measuring bit flip times for the parts of the semiconductor device irradiated with the laser light. With this method, the present invention solves the problem in the existing state of the art.

Description

ソフトエラー検査方法、ソフトエラー検査装置及びソフトエラー検査システムSoft error inspection method, soft error inspection device and soft error inspection system
　本発明は、ソフトエラー検査方法、ソフトエラー検査装置及びソフトエラー検査システムに関するものである。 The present invention relates to a soft error inspection method, a soft error inspection apparatus and a soft error inspection system.
　ＬＳＩ（Large Scale Integration）等の半導体デバイスでは、放射線による誤動作、いわゆるソフトエラーが生じることが知られている。このようなソフトエラーは、インフラ系サーバやスパコンなどのミッションクリティカルな機器だけでなく、宇宙用や医療用等の耐放射線が求められる装置、ＦＡ（Factory Automation）機器や通信基地局機材等の２４時間止められない装置においては、課題となっている。 In semiconductor devices such as LSI (Large Scale Integration), it is known that a malfunction due to radiation, that is, a so-called soft error occurs. Such soft errors are not only mission-critical devices such as infrastructure servers and supercomputers, but also devices that require radiation resistance such as for space and medical use, and 24 such as FA (Factory Automation) equipment and communication base station equipment. In devices that can not be stopped for time, it is an issue.
　一般に、ソフトエラーは欠陥が残らないため検査が困難である。具体的には、ソフトエラーの検査方法としては、高地でのランニング試験や加速器を使った試験等がある。加速器を使った試験は、更に、中性子やイオンをＬＳＩチップの全面に照射する方法と、集光可能な電子やレーザ光を局所的に照射する方法とに分けられる。これらの方法のうち、レーザ評価法は、真空にする必要がないため小規模な機材で実現可能であり、また特定のメモリ領域を個別に評価できる点で優れている。 In general, soft errors are difficult to inspect because no defects remain. Specifically, there are a running test in high altitude, a test using an accelerator, and the like as a method of inspecting soft errors. Tests using an accelerator can be further divided into a method of irradiating neutrons or ions to the entire surface of the LSI chip and a method of locally irradiating collectable electrons or laser light. Among these methods, the laser evaluation method can be realized with small-scale equipment because it does not need to be vacuum, and is excellent in that a specific memory area can be individually evaluated.
特開平５－３１３０００号公報Japanese Patent Application Laid-Open No. 5-313000 特表２０１２－５１２４０９号公報JP 2012-512409 Publication
　レーザ評価法では、赤外域の波長（例えば、１５００ｎｍ）のレーザ光を用いて二光子吸収という過程を経て電荷を発生させる。具体的には、ＬＳＩチップ等の半導体デバイスの表面側にはトランジスタ等が形成されており、これらのトランジスタ等に接続される配線等が金属材料により形成されているため、半導体デバイスの裏面側よりレーザ光を照射して検査を行う。従って、レーザ光をトランジスタが形成されている部分に、所定のパワーで照射するためには、裏面から表面側のトランジスタが形成されている部分までの距離、即ち、半導体デバイスの厚さが所定の厚さとなるようにシリコン基板の裏面を研磨する必要がある。 In the laser evaluation method, charges are generated through a process of two-photon absorption using laser light of a wavelength in the infrared region (for example, 1500 nm). Specifically, transistors and the like are formed on the surface side of a semiconductor device such as an LSI chip, and wires and the like connected to these transistors and the like are formed of a metal material. The inspection is performed by irradiating a laser beam. Therefore, in order to irradiate the portion where the transistor is formed with the laser light with a predetermined power, the distance from the back surface to the portion where the transistor on the front side is formed, that is, the thickness of the semiconductor device is predetermined. It is necessary to polish the back surface of the silicon substrate so as to have a thickness.
　しかしながら、半導体デバイスの裏面から表面側のトランジスタが形成されている部分までの距離、即ち、半導体デバイスの厚さが、全面にわたり略一定の厚さとなるように研磨することは極めて困難である。このため、レーザ評価法により半導体デバイスのソフトエラー検査を行う場合、正確な検査を行うことができなかった。尚、研磨に熟練した人であれば、時間と労力をかけることにより、半導体デバイスの厚さが略均一になるように研磨することは可能であるかもしれない。しかしながら、この場合には多大な時間と労力を要するためスループットの低下招き、また、半導体デバイスの厚さを研磨により完全に均一にすることはほぼ不可能であるため、厳密にはソフトエラー検査を正確には行うことができない。 However, it is extremely difficult to polish so that the distance from the back surface of the semiconductor device to the portion where the transistor on the front side is formed, that is, the thickness of the semiconductor device, becomes substantially constant over the entire surface. For this reason, when performing a soft error inspection of a semiconductor device by a laser evaluation method, an accurate inspection could not be performed. It should be noted that if skilled in polishing, it may be possible to polish so that the thickness of the semiconductor device becomes substantially uniform by spending time and effort. However, in this case, much time and labor are required to cause a decrease in throughput, and since it is almost impossible to make the thickness of the semiconductor device completely uniform by polishing, strictly the soft error inspection It can not be done exactly.
　このため、レーザ評価法によるソフトエラー検査方法において、半導体デバイスのソフトエラーの評価を正確、かつ、迅速に行うことのできる方法が求められている。 For this reason, in the soft error inspection method by the laser evaluation method, there is a demand for a method capable of performing the evaluation of the soft error of the semiconductor device accurately and quickly.
　本実施の形態の一観点によれば、半導体デバイスにおけるソフトエラー検査方法において、前記半導体デバイスの裏面を研磨する工程と、前記研磨の後に、前記半導体デバイスのソフトエラー検査領域における複数の部分の厚さを測定する工程と、前記半導体デバイスの厚さに対応する波長のレーザ光を前記半導体デバイスの裏面に照射する工程と、前記半導体デバイスの前記レーザ光が照射されている部分のビット反転の時間を測定する工程と、を有することを特徴とする。 According to one aspect of the present embodiment, in the soft error inspection method for a semiconductor device, the step of polishing the back surface of the semiconductor device, and the thickness of a plurality of portions in the soft error inspection region of the semiconductor device after the polishing Measuring the thickness, irradiating the back surface of the semiconductor device with a laser beam having a wavelength corresponding to the thickness of the semiconductor device, and inverting the bit of the portion of the semiconductor device irradiated with the laser light And measuring.
　開示のソフトエラー検査方法によれば、半導体デバイスのソフトエラーの評価を正確、かつ、迅速に行うことができる。 According to the disclosed soft error inspection method, it is possible to evaluate soft errors of semiconductor devices accurately and quickly.
半導体デバイスの裏面研磨の説明図（１）An explanatory view (1) of back surface polishing of a semiconductor device 半導体デバイスの裏面研磨の説明図（２）An explanatory view (2) of the back surface polishing of a semiconductor device シリコンに照射される光の波長と透過深さとの相関図Correlation diagram of wavelength of light irradiated to silicon and penetration depth 本実施の形態におけるソフトエラー検査装置の構造図Structure diagram of the soft error inspection device in the present embodiment 本実施の形態におけるソフトエラー検査方法のフローチャートFlow chart of soft error inspection method in the present embodiment 本実施の形態に用いられる波長制御条件テーブルの説明図Explanation of wavelength control condition table used in the present embodiment 本実施の形態におけるソフトエラー検査方法の説明図（１）Explanatory drawing (1) of the soft error inspection method in this embodiment 本実施の形態におけるソフトエラー検査方法の説明図（２）Explanatory drawing (2) of the soft error inspection method in this embodiment
　実施するための形態について、以下に説明する。尚、同じ部材等については、同一の符号を付して説明を省略する。 A mode for carrying out will be described below. In addition, about the same member etc., the same code | symbol is attached | subjected and description is abbreviate | omitted.
　最初に、ソフトエラー及びソフトエラー検査方法の概要について説明する。高エネルギービームがＬＳＩチップ内部に入射するとエネルギーが失われつつも進み続け、その飛跡に沿って電子・正孔対が生成される。これらの電荷が電極に移動してストレージノード内に流入し、閾値以上の電荷になると、それまで記録されていたビット情報が反転する（０→１、または、１→０）。この現象はシングルイベントアップセット（ＳＥＵ：Single Event Upset）と呼ばれ、ＬＳＩチップ内メモリの最大の誤動作要因である。 First, an outline of the soft error and the soft error inspection method will be described. When the high energy beam is incident on the inside of the LSI chip, it continues to travel while losing energy, and electron-hole pairs are generated along the track. When these charges move to the electrodes and flow into the storage node and become charges above the threshold value, the bit information recorded until then is inverted (0 → 1 or 1 → 0). This phenomenon is called single event upset (SEU) and is the largest malfunction source of the memory in the LSI chip.
　後述するように、本実施の形態においては、ＳＥＵを加速評価するためエネルギービームを用いているが、電子線等の荷電粒子と、レーザ光とではＳＥＵの発生メカニズムが異なる。電子線等の荷電粒子の場合では、ＬＳＩチップに電子線等の荷電粒子を照射することにより、電離作用により電子・正孔対が生成される。これに対し、レーザ光の場合では、ＬＳＩチップにレーザ光を照射すると、二光子吸収といって２個の光子を同時に吸収する励起過程により、電子・正孔対が生成される。具体的には、光子によるエネルギーがＳｉのバンドギャップエネルギーである１．１２ｅＶを上回れば、間接遷移により電子・正孔対が生成される。このように、電子線等の荷電粒子とレーザ光では電子・正孔対の発生メカニズムは異なるが、その後のＳＥＵを誘起する過程は同じである。 As described later, in the present embodiment, an energy beam is used to accelerate and evaluate the SEU. However, the generation mechanism of the SEU is different between the charged particles such as the electron beam and the laser beam. In the case of charged particles such as electron beams, electron-hole pairs are generated by the ionization action by irradiating the LSI chip with charged particles such as electron beams. On the other hand, in the case of the laser light, when the LSI chip is irradiated with the laser light, an electron-hole pair is generated by an excitation process which simultaneously absorbs two photons as two-photon absorption. Specifically, when the energy by the photon exceeds 1.12 eV which is the band gap energy of Si, the electron-hole pair is generated by the indirect transition. As described above, the generation mechanism of electron-hole pairs is different between charged particles such as electron beams and laser light, but the process of inducing the subsequent SEU is the same.
　上記のように、レーザ評価法により半導体デバイスのソフトエラー検査を行う際には、シリコン基板の裏面より研磨を行う。具体的には、図１に示されるように、半導体デバイス１０のシリコン基板の表面１０ａには、トランジスタ形成層１１が形成されている。トランジスタ形成層１１には、トランジスタとトランジスタに接続される金属により形成された配線等が形成されており、このような配線等はソフトエラー検査を行う際に障害となる場合がある。従って、半導体デバイス１０のシリコン基板の裏面１０ｂ側より赤外線を照射するため、半導体デバイス１０のシリコン基板の裏面１０ｂの研磨を行う。 As described above, when the soft error inspection of the semiconductor device is performed by the laser evaluation method, the polishing is performed from the back surface of the silicon substrate. Specifically, as shown in FIG. 1, a transistor forming layer 11 is formed on the surface 10 a of the silicon substrate of the semiconductor device 10. In the transistor formation layer 11, a transistor and a wire or the like formed of metal connected to the transistor are formed, and such a wire or the like may become an obstacle when performing a soft error test. Therefore, in order to irradiate infrared rays from the back surface 10b side of the silicon substrate of the semiconductor device 10, the back surface 10b of the silicon substrate of the semiconductor device 10 is polished.
　この場合、図１（ａ）に示すように、半導体デバイス１０のシリコン基板の裏面１０ｂからトランジスタ形成層１１までの距離が同じとなるように、即ち、半導体デバイス１０のシリコン基板の裏面１０ｂと表面１０ａとが平行となるように研磨する必要がある。しかしながら、このような研磨は極めて困難であり、実際に研磨を行うと、図１（ｂ）に示すように、半導体デバイス１０のシリコン基板の裏面１０ｂは、表面１０ａに対し傾斜してしまう。このような傾向は、研磨に慣れていない人が行った場合に、より一層顕著となる。 In this case, as shown in FIG. 1A, the distance from the back surface 10b of the silicon substrate of the semiconductor device 10 to the transistor forming layer 11 is the same, that is, the back surface 10b and the front surface of the silicon substrate of the semiconductor device 10. It is necessary to polish so that it is parallel to 10a. However, such polishing is extremely difficult, and when the polishing is actually performed, the back surface 10b of the silicon substrate of the semiconductor device 10 is inclined with respect to the surface 10a as shown in FIG. 1 (b). Such a tendency becomes even more pronounced when the person who is not accustomed to polishing performs.
　図１（ｂ）に示すように、半導体デバイス１０のシリコン基板の裏面１０ｂが、表面１０ａに対し傾斜していると、半導体デバイス１０のシリコン基板の裏面１０ｂから表面側のトランジスタ形成層１１までの距離が場所によって異なってしまう。従って、ソフトエラー検査のために赤外域のレーザ光を照射した場合、トランジスタ形成層１１に到達するまでの透過率も異なるため、正確なソフトエラー検査を行うことができない。 As shown in FIG. 1B, when the back surface 10b of the silicon substrate of the semiconductor device 10 is inclined with respect to the front surface 10a, from the back surface 10b of the silicon substrate of the semiconductor device 10 to the transistor forming layer 11 on the front side. The distance varies depending on the place. Therefore, when the laser beam in the infrared region is irradiated for the soft error inspection, the transmittance until reaching the transistor forming layer 11 is also different, so that the accurate soft error inspection can not be performed.
　尚、半導体デバイス１０のシリコン基板の裏面１０ｂの研磨の方法としては、上記以外には、半導体デバイス１０のシリコン基板の裏面１０ｂにディンプル面１０ｃを形成するディンプル研磨のような局所研磨がある。しかしながら、このようなディンプル研磨では、検査したい所望の位置の裏面１０ｂに正確にディンプル面１０ｃを形成する必要があるが、半導体デバイス１０のシリコン基板の所望の位置の裏面１０ｂに正確にディンプル面１０ｃを形成することは極めて困難である。また、ディンプル研磨では、ディンプル面１０ｃにおける厚さは部分ごとに異なる。 As a method of polishing the back surface 10b of the silicon substrate of the semiconductor device 10, there is local polishing such as dimple polishing for forming the dimple surface 10c on the back surface 10b of the silicon substrate of the semiconductor device 10 other than the above. However, in such dimple polishing, although it is necessary to form the dimple surface 10 c accurately on the back surface 10 b at the desired position to be inspected, the dimple surface 10 c exactly on the back surface 10 b of the silicon substrate of the semiconductor device 10 at the desired position. It is extremely difficult to form Further, in dimple polishing, the thickness of the dimple surface 10c differs from part to part.
　以上のように、半導体デバイスのソフトエラーの評価を行う際には、半導体デバイスのシリコン基板の裏面から研磨を行う必要があるが、シリコン基板の厚さが均一になるように研磨することは極めて困難である。このため、半導体デバイスのソフトエラーの検査を正確、かつ、簡単で迅速に行うことのできるレーザ評価法によるソフトエラー検査方法が求められている。 As described above, when evaluating soft errors in a semiconductor device, it is necessary to polish from the back surface of the silicon substrate of the semiconductor device, but it is extremely difficult to polish so that the thickness of the silicon substrate becomes uniform. Have difficulty. Therefore, there is a need for a soft error inspection method using a laser evaluation method that can perform soft error inspection of semiconductor devices accurately, easily and quickly.
　ところで、シリコンが用いられている半導体デバイスにおいては、二光子吸収が起きる赤外光の波長は１．１μｍ～２．１μｍであるが、シリコンにおける透過率は波長（エネルギー）に依存しており、照射される赤外光の波長が変化すると透過率も変化する。図３は、シリコンにおいて、照射される光の波長と透過深さとの関係を示す。図３に示されるように、シリコンに照射される光の波長が変化するとシリコンにおける透過深さも変化する。 By the way, in a semiconductor device in which silicon is used, the wavelength of infrared light that causes two-photon absorption is 1.1 μm to 2.1 μm, but the transmittance in silicon depends on the wavelength (energy), When the wavelength of infrared light to be irradiated changes, the transmittance also changes. FIG. 3 shows the relationship between the wavelength of the light to be irradiated and the penetration depth in silicon. As shown in FIG. 3, when the wavelength of light irradiated to silicon changes, the penetration depth in silicon also changes.
　図３は、非特許文献１の記載に基づくものであり、透過深さは吸光度測定から定義することができる。既知の波長、試料厚さに対して入射光と出射光の比を取り、完全に吸収されれば吸光度は１、透過率は０となり、その厚さをプロットしたものが図３である。図３は光がそれ以上侵入できない深さともいうことができる。尚、吸光度と透過性の関係性は、Ａを吸光度、Ｉ０を入射光強度、Ｉを試料通過後の光（出射光）の強度とした場合、Ａ＝－ｌｏｇ１０（Ｉ／Ｉ０）となり、透過率はＩ／Ｉ０である。 FIG. 3 is based on the description of Non-Patent Document 1, and the penetration depth can be defined from absorbance measurement. Taking the ratio of incident light to outgoing light to a known wavelength and sample thickness, the absorbance is 1 when the light is completely absorbed, the transmittance is 0, and the thickness is plotted in FIG. FIG. 3 can also be referred to as a depth where light can not penetrate further. The relationship between the absorbance and the transmittance is as follows: A = -log 10 (I / I 0 ), where A is absorbance, I 0 is incident light intensity, and I is intensity of light after passing through the sample (emitted light). And the transmittance is I / I 0 .
　また、シリコンに不純物元素がドープされている場合には、ドープされている不純物元素の濃度に対応して、透過深さの値も変化する。具体的には、図３に示されるように、不純物元素がドープされているシリコンでは、波長が１．１μｍ～１．２μｍの赤外光の透過率が最も高く、ドープされている不純物の濃度に依存して透過深さが変化し、例えば、数十μｍから数百μｍまで変化する。尚、Ｎ＝２．４×１０１９ｃｍ－３は、シリコンにＮ型となる不純物元素が２．４×１０１９ｃｍ－３の濃度でドープされているものである。また、Ｎ＝６×１０１８ｃｍ－３は、シリコンにＮ型となる不純物元素が６×１０１８ｃｍ－３の濃度でドープされているものである。 In addition, when silicon is doped with an impurity element, the value of penetration depth also changes in accordance with the concentration of the doped impurity element. Specifically, as shown in FIG. 3, in silicon doped with an impurity element, the transmittance of infrared light having a wavelength of 1.1 μm to 1.2 μm is the highest, and the concentration of the doped impurity is high. Depending on the depth of penetration, for example, from several tens of μm to several hundreds of μm. Here, N = 2.4 × 10 19 cm −3 is obtained by doping silicon with an N-type impurity element at a concentration of 2.4 × 10 19 cm −3 . Further, N = 6 × 10 18 cm -3 is one in which silicon is doped with an impurity element to be N-type at a concentration of 6 × 10 18 cm -3 .
　このため、シリコン基板に不純物元素がドープされている半導体デバイスの検査を行う場合には、図３に示されるように、照射される光の波長と透過深さとの関係が既知である場合には、その関係を用いることができる。また、既知ではない場合には、ドープされている不純物元素の濃度が既知であるシリコン基板を準備し、そのシリコン基板において、波長を変化させた場合における透過率や透過深さを測定し、波長と透過深さとの関係のグラフやテーブル等を作成してもよい。 Therefore, when a semiconductor device in which a silicon substrate is doped with an impurity element is inspected, as shown in FIG. 3, if the relationship between the wavelength of the light to be irradiated and the transmission depth is known. , That relationship can be used. Also, if it is not known, prepare a silicon substrate in which the concentration of the doped impurity element is known, and measure the transmittance and transmission depth when the wavelength is changed on the silicon substrate. You may create a graph, a table, etc. of the relationship between and the penetration depth.
　ところで、半導体デバイスであるＬＳＩチップの厚さは、仕様により様々であり、例えば、チップ化された時点で厚さが約１００μｍまでバックグラインドされているものや、厚さが約１ｍｍ程度のものまである。レーザ評価法によるソフトエラー検査方法では、レーザ光をＬＳＩチップのシリコン基板の裏面から照射して、トランジスタが形成されているトランジスタ形成層まで透過させる必要がある。このため、ＬＳＩチップのシリコン基板の厚さが厚い場合には、裏面から研磨し薄くする必要があるが、シリコン基板を裏面より研磨して、全体的に厚さが数μｍ程度となるようにすることは困難である。尚、シリコン基板は、厚さが５０μｍ程度であれば、研磨に関するノウハウがなくとも、シリコン基板が割れたり破損したりすることなく、比較的容易に研磨することができる。 By the way, the thickness of an LSI chip which is a semiconductor device varies depending on the specification. For example, when it is made into a chip, it is back ground to about 100 μm in thickness, or to about 1 mm in thickness. is there. In the soft error inspection method by the laser evaluation method, it is necessary to irradiate the laser light from the back surface of the silicon substrate of the LSI chip to transmit it to the transistor formation layer in which the transistor is formed. For this reason, when the silicon substrate of the LSI chip is thick, it is necessary to polish it from the back and make it thinner. However, the silicon substrate is polished from the back so that the thickness becomes about several μm as a whole. It is difficult to do. If the silicon substrate has a thickness of about 50 μm, it can be relatively easily polished without cracking or breakage of the silicon substrate without knowing how to polish.
　ところで、ソフトエラーの原因となる電荷を発生させる場所は、シリコン基板の表面側のトランジスタが形成されているトランジスタ形成層である。従って、本実施の形態においては、裏面が研磨されたシリコン基板の検査対象となる領域における各々の部分の厚さを測定し、各々の部分における透過率が略一定になるように赤外光の波長を設定し照射する。即ち、シリコン基板の厚さに応じて、透過率が略一定となるように赤外光の波長を変化させてシリコン基板に照射する。これにより、シリコン基板の表面側に形成されているトランジスタ形成層に入射する赤外光の強度を均一にすることができ、シリコン基板の厚さが部分ごとに異なる場合であっても、正確なソフトエラーの検査を行うことが可能となる。 By the way, the place where the charge causing the soft error is generated is the transistor forming layer in which the transistor on the surface side of the silicon substrate is formed. Therefore, in the present embodiment, the thickness of each portion in the region to be inspected of the silicon substrate whose back surface is polished is measured, and the transmittance of the infrared light is substantially constant in each portion. Set the wavelength and irradiate. That is, in accordance with the thickness of the silicon substrate, the wavelength of infrared light is changed so that the transmittance is substantially constant, and the silicon substrate is irradiated. This makes it possible to make the intensity of the infrared light incident on the transistor forming layer formed on the surface side of the silicon substrate uniform, and accurate even when the thickness of the silicon substrate differs from part to part. It is possible to check for soft errors.
　シリコン基板の検査対象となる領域の厚さの測定は、共焦点顕微鏡や光干渉計等の干渉顕微鏡を用いて行うことができる。本実施の形態においては、半導体デバイスのシリコン基板の厚さをソフトエラーの検査の対象となる領域の部分ごとに測定し、測定された厚さに基づき波長を変化させながらレーザ光を照射して、ソフトエラーの検査を行う。これにより、ソフトエラーの検査を正確、かつ、迅速に行うことができる。 The thickness of the region to be inspected of the silicon substrate can be measured using an interference microscope such as a confocal microscope or an optical interferometer. In the present embodiment, the thickness of the silicon substrate of the semiconductor device is measured for each part of the area to be subjected to the soft error inspection, and laser light is irradiated while changing the wavelength based on the measured thickness. Check for soft errors. This makes it possible to check soft errors accurately and quickly.
　（ソフトエラー検査装置及びソフトエラー検査システム）
　次に、本実施の形態におけるソフトエラー検査装置について説明する。図４は、本実施の形態におけるソフトエラー検査装置及びソフトエラー検査システムを示す。本実施の形態におけるソフトエラー検査装置は、走査ステージ２０、走査制御部２１、照射源３０、照射制御部３１、基板厚測定部４０、基板厚測定制御部４１、測定器５０、制御部６０等を有している。制御部６０は、情報処理部６１、記憶部６２を有しており、表示部６３及び入力部６４が接続されている。 (Soft error inspection device and soft error inspection system)
Next, the soft error inspection apparatus according to the present embodiment will be described. FIG. 4 shows a soft error inspection apparatus and a soft error inspection system according to the present embodiment. The soft error inspection apparatus according to the present embodiment includes a scan stage 20, a scan control unit 21, an irradiation source 30, an irradiation control unit 31, a substrate thickness measurement unit 40, a substrate thickness measurement control unit 41, a measuring unit 50, a control unit 60, and the like. have. The control unit 60 includes an information processing unit 61 and a storage unit 62, and the display unit 63 and the input unit 64 are connected.
　検査対象となる試料である半導体デバイス１０は、ＬＳＩチップ等であり、半導体デバイス１０は走査ステージ２０の上に設置され、走査ステージ２０により２次元、即ち、Ｘ軸方向及びＹ軸方向に動かすことができる。走査ステージ２０は、走査制御部２１により制御される。尚、本実施の形態においては、半導体デバイス１０は、図１（ａ）または図１（ｂ）に示されるものである。 The semiconductor device 10 which is a sample to be inspected is an LSI chip or the like, and the semiconductor device 10 is installed on the scanning stage 20 and moved in two dimensions, ie, the X axis direction and the Y axis direction by the scanning stage 20 Can. The scanning stage 20 is controlled by the scanning control unit 21. In the present embodiment, the semiconductor device 10 is as shown in FIG. 1 (a) or FIG. 1 (b).
　照射源３０は、半導体デバイス１０に照射されるレーザ光を出射するものであり、波長を変化させることのできる波長可変レーザであって、照射制御部３１により制御される。本実施の形態においては、照射源３０からレーザ光が出射される場合について説明するが、電子線等の荷電粒子が出射されるものであってもよい。半導体デバイス１０がシリコンにより形成された半導体デバイスである場合には、シリコンにおいて二光子吸収が生じる波長領域が１１００ｎｍ～２１００ｎｍであるため、例えば、照射源３０より出射されるレーザ光の波長は、約１５００ｎｍである。 The irradiation source 30 emits a laser beam irradiated to the semiconductor device 10, is a variable-wavelength laser capable of changing the wavelength, and is controlled by the irradiation control unit 31. In the present embodiment, although a case where laser light is emitted from the irradiation source 30 will be described, charged particles such as an electron beam may be emitted. In the case where the semiconductor device 10 is a semiconductor device formed of silicon, for example, the wavelength of the laser light emitted from the irradiation source 30 is about approximately because the wavelength region where two-photon absorption occurs in silicon is 1100 nm to 2100 nm. It is 1500 nm.
　基板厚測定部４０は、共焦点顕微鏡や光干渉計等の干渉顕微鏡であり、基板厚測定制御部４１により制御される。測定器５０は、テスタ等であり、半導体デバイス１０の端子に接続されており、半導体デバイス１０内に記憶されている情報の変化を測定することができる。 The substrate thickness measurement unit 40 is an interference microscope such as a confocal microscope or an optical interferometer, and is controlled by the substrate thickness measurement control unit 41. The measuring device 50 is a tester or the like, is connected to the terminal of the semiconductor device 10, and can measure a change in information stored in the semiconductor device 10.
　制御部６０は、本実施の形態におけるソフトエラー検査装置全体の制御及びソフトエラー検査方法に関する情報処理動作を行うものであり、走査制御部２１、照射制御部３１、基板厚測定制御部４１、測定器５０等が接続されている。また、情報処理部６１には、情報を記憶する記憶部６２、必要な情報を表示するための表示部６３、情報処理部６１に情報を入力するための入力部６４等が接続されている。本実施の形態においては、制御部６０における制御により、以下に説明するソフトエラー検査方法を実行することができるソフトエラー検査システムとなっている。 The control unit 60 performs control of the entire soft error inspection apparatus according to the present embodiment and information processing operation related to the soft error inspection method, and the scan control unit 21, the irradiation control unit 31, the substrate thickness measurement control unit 41, and the measurement The vessel 50 and the like are connected. The information processing unit 61 is connected to a storage unit 62 for storing information, a display unit 63 for displaying necessary information, and an input unit 64 for inputting information to the information processing unit 61. In the present embodiment, the control of the control unit 60 is a soft error inspection system capable of executing the soft error inspection method described below.
　（ソフトエラー検査方法）
　次に、本実施の形態におけるソフトエラー検査方法について、図５に基づき説明する。本実施の形態におけるソフトエラー検査方法の検査の対象となる半導体デバイス１０は、ＳＲＡＭ（Static Random Access Memory）、フラッシュメモリ、ＦＰＧＡ（field-programmable gate array）、ＡＳＩＣ（application specific integrated circuit）等である。本実施の形態におけるソフトエラー検査方法は、制御部６０における制御に基づき行われる。尚、本実施の形態においては、シリコンに照射される赤外光の波長と透過深さとの関係は予め測定されているか、または、文献等より得られているものとし、この情報は記憶部６２に記憶されているものとする。 (Soft error inspection method)
Next, a soft error inspection method according to the present embodiment will be described based on FIG. The semiconductor device 10 to be inspected in the soft error inspection method in the present embodiment is a static random access memory (SRAM), a flash memory, a field-programmable gate array (FPGA), an application specific integrated circuit (ASIC) or the like. . The soft error inspection method according to the present embodiment is performed based on the control of the control unit 60. In the present embodiment, it is assumed that the relationship between the wavelength of infrared light irradiated to silicon and the transmission depth is measured in advance or obtained from literature or the like, and this information is stored in the storage unit 62. Shall be stored in
　最初に、ステップ１０２（Ｓ１０２）において、ソフトエラーの検査対象となる半導体デバイス１０におけるシリコン基板の裏面を研磨する。具体的には、半導体デバイス１０のシリコン基板の厚さが、約５０μｍ程度となるように研磨する。この厚さであれば、シリコン基板において割れや破損が生じないからである。本実施の形態においては、研磨後のシリコン基板の厚さにバラツキ等があってもよい。 First, in step 102 (S102), the back surface of the silicon substrate in the semiconductor device 10 to be inspected for soft errors is polished. Specifically, the silicon substrate of the semiconductor device 10 is polished so as to have a thickness of about 50 μm. With this thickness, no cracking or damage occurs in the silicon substrate. In the present embodiment, the thickness of the silicon substrate after polishing may have variations or the like.
　次に、ステップ１０４（Ｓ１０４）からステップ１０８（Ｓ１０８）では、半導体デバイス１０のソフトエラーの検査対象となる領域（ソフトエラー検査領域）における複数の部分の厚さを各々部分ごとに２次元的に測定する。これにより、ソフトエラー検査領域における厚さの２次元情報を得る。 Next, in steps 104 (S104) to 108 (S108), the thicknesses of a plurality of portions in the region (soft error inspection region) to be inspected for soft errors in the semiconductor device 10 are two-dimensionally provided for each portion. taking measurement. Thereby, two-dimensional information of thickness in the soft error inspection area is obtained.
　具体的には、ステップ１０４では、半導体デバイス１０のソフトエラーの検査対象となる領域のある部分の厚さを基板厚測定部４０により測定し、ステップ１０６（Ｓ１０６）に移行する。ステップ１０６では、半導体デバイス１０のソフトエラーの検査対象となる領域の部分ごとの厚さの測定が終了したか否か、即ち、検査対象となる領域の部分ごとの厚さを測定するための走査が終了したか否かを判断する。ソフトエラーの検査対象となる領域の部分ごとの厚さを測定するための走査が終了した場合には、ステップ１１０に移行し、ソフトエラーの検査対象となる領域の部分ごとの厚さを測定するための走査が終了していない場合には、ステップ１０８に移行する。ステップ１０８では、半導体デバイス１０のソフトエラーの検査対象となる領域内において、次に厚さが測定される部分に位置を動かし、ステップ１０４に移行する。この後、ステップ１０４において、位置が動かされた次に厚さが測定される部分の半導体デバイス１０の厚さを測定する。このように、ステップ１０４からステップ１０８の工程を繰り返して行うことにより、半導体デバイス１０のソフトエラーの検査対象となる領域における厚さの分布のマップを作成する。この情報は、制御部６０内の記憶部６２に記憶される。 Specifically, in step 104, the thickness of a portion of the semiconductor device 10 in which the region to be inspected for soft errors is measured by the substrate thickness measurement unit 40, and the process proceeds to step 106 (S106). In step 106, whether or not the measurement of the thickness for each portion of the area to be inspected for soft errors in the semiconductor device 10 is completed, ie, the scan for measuring the thickness for each portion of the area to be inspected To determine if the If scanning for measuring the thickness of each part of the area to be inspected for soft errors is completed, the process proceeds to step 110, and the thickness for each part of the area to be inspected for soft errors is measured. If the scanning for the image has not been completed, the process proceeds to step 108. In step 108, the position of the semiconductor device 10 in the area to be inspected for soft errors is moved to the portion where the thickness is to be measured next, and the process moves to step 104. Thereafter, in step 104, the thickness of the semiconductor device 10 of the portion whose position has been moved and whose thickness is to be measured is measured. As described above, the process of step 104 to step 108 is repeated to create a map of the distribution of thickness in the area to be inspected for the soft error of the semiconductor device 10. This information is stored in the storage unit 62 in the control unit 60.
　次に、ステップ１１０（Ｓ１１０）において、半導体デバイス１０における不純物濃度の値を入力する。具体的には、半導体デバイス１０における不純物濃度の値が既知であれば、その値を入力部６４より入力する。また、既知でない場合には、様々な方法により半導体デバイス１０における不純物濃度の値を測定し入力してもよい。 Next, in step 110 (S110), the value of the impurity concentration in the semiconductor device 10 is input. Specifically, if the value of the impurity concentration in the semiconductor device 10 is known, the value is input from the input unit 64. Also, if not known, the value of the impurity concentration in the semiconductor device 10 may be measured and input by various methods.
　次に、ステップ１１２（Ｓ１１２）において、入力された半導体デバイス１０の不純物濃度の値に基づき、照射される透過率が均一となるように、ステップ１０４からステップ１０８において測定された半導体デバイス１０の厚さに対応した赤外光の波長を抽出する。 Next, in step 112 (S112), the thickness of the semiconductor device 10 measured in steps 104 to 108 so that the irradiated transmittance becomes uniform based on the value of the impurity concentration of the semiconductor device 10 input. Extract the wavelength of infrared light corresponding to.
　次に、ステップ１１４（Ｓ１１４）において、ステップ１１２において抽出された波長に基づき波長制御条件テーブルを作成する。波長制御条件テーブルは、例えば、図６に示されるように、半導体デバイス１０の厚さに対応した赤外光の波長が２次元状にＭ行Ｎ列で配列されているものであり、記憶部６２に記憶される。 Next, in step 114 (S114), a wavelength control condition table is created based on the wavelength extracted in step 112. The wavelength control condition table is, for example, as shown in FIG. 6, in which the wavelengths of infrared light corresponding to the thickness of the semiconductor device 10 are two-dimensionally arranged in M rows and N columns, and the storage unit It is stored in 62.
　次に、ステップ１１６（Ｓ１１６）において、図６に示される波長制御条件テーブルに基づき、レーザ光の波長を変化させながら、検査対象となる半導体デバイス１０に、所定の時間、レーザ光を照射することにより、ソフトエラーの検査を行う。具体的には、図７に示されるように、半導体デバイス１０の所定の位置にレーザ光を所定の時間照射し、レーザ光が照射されている位置のビット情報の時系列データを測定し、記憶部６２等に記憶する。 Next, in step 116 (S116), the semiconductor device 10 to be inspected is irradiated with the laser light for a predetermined time while changing the wavelength of the laser light based on the wavelength control condition table shown in FIG. Check for soft errors. Specifically, as shown in FIG. 7, a predetermined position of the semiconductor device 10 is irradiated with laser light for a predetermined time, and time-series data of bit information of the position where the laser light is irradiated is measured and stored. It stores in part 62 grade.
　具体的には、図７に示されるように、レーザ光が照射されている状態で、テスタ等の測定器５０により、レーザ光が照射されている位置のビット情報の時系列データ、即ち、ビット情報の時間的変化を測定し、記憶部６２等に記憶する。図８は、測定器５０により検出されたレーザ光が照射されている位置のビット情報の時系列データを示す。図８（ａ）は、レーザ光の照射開始より、時間ｔ１が経過した時点で、ビット情報が０→１に反転している様子を示す。図８（ｂ）は、レーザ光の照射開始より、時間ｔ２が経過した時点で、ビット情報が０→１に反転している様子を示す。図８（ｃ）は、レーザ光の照射開始より、時間ｔ３が経過した時点で、ビット情報が０→１に反転し、更に、時間ｔ４が経過した時点で、ビット情報が１→０に再反転している様子を示す。尚、本願においては、ビット情報の反転をビット反転と記載する場合がある。 Specifically, as shown in FIG. 7, time-series data of bit information of a position where the laser light is irradiated by the measuring device 50 such as a tester while the laser light is irradiated, ie, a bit The temporal change of information is measured and stored in the storage unit 62 or the like. FIG. 8 shows time-series data of bit information of a position where the laser light detected by the measuring device 50 is irradiated. FIG. 8A shows that bit information is inverted from 0 to 1 when time t1 has elapsed from the start of laser beam irradiation. FIG. 8 (b), at the time from the start of laser beam irradiation, the time t 2 has passed, showing that bit information is reversed to 0 → 1. In FIG. 8C, the bit information is inverted from 0 to 1 when time t 3 elapses from the start of laser light irradiation, and the bit information is 1 → 0 when time t 4 elapses. It shows how it re-reverses. In the present application, inversion of bit information may be described as bit inversion.
　このような測定を半導体デバイス１０においてソフトエラーの検査対象となる領域において、測定する場所を変えるとともに、レーザ光の波長を変化させて、レーザ光を走査して測定を行う。 While changing the place to measure in the area | region which becomes an inspection object of a soft error in the semiconductor device 10 in such a measurement, the wavelength of a laser beam is changed and a laser beam is scanned and measured.
　以上により、本実施の形態におけるソフトエラー検査方法は終了する。 Thus, the soft error inspection method according to the present embodiment ends.
　本実施の形態におけるソフトエラー検査方法によれば、半導体デバイス１０の厚さが均一ではない場合であっても、ソフトエラーの検査対象となる領域において、正確な検査を行うことができる。 According to the soft error inspection method in the present embodiment, even if the thickness of the semiconductor device 10 is not uniform, accurate inspection can be performed in the area to be inspected for soft errors.
　以上、実施の形態について詳述したが、特定の実施形態に限定されるものではなく、特許請求の範囲に記載された範囲内において、種々の変形及び変更が可能である。 As mentioned above, although an embodiment was explained in full detail, it is not limited to a specific embodiment, and various modification and change are possible within the limits indicated in a claim.
１０　　　　半導体デバイス
２０　　　　走査ステージ
２１　　　　走査制御部
３０　　　　照射源
３１　　　　照射制御部
４０　　　　基板厚測定部
４１　　　　基板厚測定制御部
５０　　　　測定器
６０　　　　制御部
６１　　　　情報処理部
６２　　　　記憶部
６３　　　　表示部
６４　　　　入力部 Reference Signs List 10 semiconductor device 20 scan stage 21 scan control unit 30 irradiation source 31 irradiation control unit 40 substrate thickness measurement unit 41 substrate thickness measurement control unit 50 measurement unit 60 control unit 61 information processing unit 62 storage unit 63 display unit 64 input unit

Claims (9)

  1. 　半導体デバイスにおけるソフトエラー検査方法において、
    　前記半導体デバイスの裏面を研磨する工程と、
    　前記研磨の後に、前記半導体デバイスのソフトエラー検査領域における複数の部分の厚さを測定する工程と、
    　前記半導体デバイスの厚さに対応する波長のレーザ光を前記半導体デバイスの裏面に照射する工程と、
    　前記半導体デバイスの前記レーザ光が照射されている部分のビット反転の時間を測定する工程と、
    　を有することを特徴とするソフトエラー検査方法。     In a soft error inspection method for a semiconductor device,
    Polishing the back surface of the semiconductor device;
    Measuring the thickness of the plurality of portions in the soft error inspection area of the semiconductor device after the polishing;
    Irradiating the back surface of the semiconductor device with laser light of a wavelength corresponding to the thickness of the semiconductor device;
    Measuring a time of bit inversion of a portion of the semiconductor device irradiated with the laser light;
    A soft error checking method comprising:
  2. 　前記半導体デバイスの厚さに対応する前記レーザ光の波長は、前記半導体デバイスのソフトエラー検査領域の複数の部分におけるレーザ光の透過率が均一になるように設定されるものであることを特徴とする請求項１に記載のソフトエラー検査方法。 The wavelength of the laser beam corresponding to the thickness of the semiconductor device is set so that the transmittance of the laser beam in a plurality of portions of the soft error inspection region of the semiconductor device becomes uniform. The soft error inspection method according to claim 1.
  3. 　前記半導体デバイスの厚さの測定は、前記半導体デバイスのソフトエラー検査領域において２次元的に行うものであって、
    　前記半導体デバイスへの前記レーザ光の照射は、前記ソフトエラー検査領域において前記レーザ光を走査しながら行うことを特徴とする請求項１または２に記載のソフトエラー検査方法。     The measurement of the thickness of the semiconductor device is performed two-dimensionally in a soft error inspection area of the semiconductor device,
    The soft error inspection method according to claim 1 or 2, wherein the irradiation of the laser light onto the semiconductor device is performed while scanning the laser light in the soft error inspection area.
  4. 　前記２次元的に測定された前記半導体デバイスの厚さに基づき、前記ソフトエラー検査領域において照射されるレーザ光の波長の分布の情報が配列された波長制御条件テーブルを作成する工程を有し、
    　前記レーザ光を走査する際には、前記波長制御条件テーブルにおける波長のレーザ光を照射することを特徴とする請求項３に記載のソフトエラー検査方法。     Creating a wavelength control condition table in which information on the distribution of the wavelength of the laser beam irradiated in the soft error inspection region is arranged based on the thickness of the semiconductor device measured two-dimensionally;
    4. The soft error inspection method according to claim 3, wherein when scanning the laser light, the laser light of the wavelength in the wavelength control condition table is irradiated.
  5. 　前記半導体デバイスの厚さは、共焦点顕微鏡、または、干渉顕微鏡により測定するものであることを特徴とする請求項１から４のいずれかに記載のソフトエラー検査方法。 The soft error inspection method according to any one of claims 1 to 4, wherein the thickness of the semiconductor device is measured by a confocal microscope or an interference microscope.
  6. 　前記ソフトエラー検査方法は、照射された前記レーザ光の二光子吸収によりなされるものであることを特徴とする請求項１から５のいずれかに記載のソフトエラー検査方法。 The soft error inspection method according to any one of claims 1 to 5, wherein the soft error inspection method is performed by two-photon absorption of the irradiated laser light.
  7. 　半導体デバイスが設置されるステージと、
    　前記半導体デバイスに照射されるレーザ光を出射する照射源と、
    　前記半導体デバイスに接続され、前記レーザ光が照射されている領域のビット反転を測定する測定器と、
    　前記半導体デバイスのソフトエラー検査領域における複数の部分の厚さを測定する基板厚測定部と、
    　前記測定器により測定された前記半導体デバイスの前記レーザ光が照射されている部分ごとのビット反転の時間を記憶する記憶部と、
    　前記半導体デバイスの厚さに対応して前記照射源より出射するレーザ光の波長を変化させる制御を行う制御部と、
    　を有することを特徴とするソフトエラー検査装置。     A stage on which a semiconductor device is installed;
    An irradiation source for emitting a laser beam irradiated to the semiconductor device;
    A measuring device connected to the semiconductor device to measure bit inversion in a region irradiated with the laser light;
    A substrate thickness measurement unit configured to measure thicknesses of a plurality of portions in a soft error inspection region of the semiconductor device;
    A storage unit for storing a time of bit inversion of each portion of the semiconductor device irradiated with the laser light, which is measured by the measuring device;
    A control unit that performs control to change the wavelength of the laser light emitted from the irradiation source according to the thickness of the semiconductor device;
    A soft error inspection device characterized by having.
  8. 　前記記憶部には、前記半導体デバイスの厚さに対応するレーザ光の波長が記憶されており、
    　前記レーザ光の波長は、前記半導体デバイスの厚さが変化しても、レーザ光の透過率が均一となるように設定されたものであることを特徴とする請求項７に記載のソフトエラー検査装置。     The storage unit stores the wavelength of the laser beam corresponding to the thickness of the semiconductor device,
    8. The soft error inspection according to claim 7, wherein the wavelength of the laser beam is set so that the transmittance of the laser beam becomes uniform even if the thickness of the semiconductor device changes. apparatus.
  9. 　請求項７または８に記載のソフトエラー検査装置を含み、前記制御部により制御がなされることを特徴とするソフトエラー検査システム。 A soft error inspection system comprising the soft error inspection device according to claim 7 or 8, wherein control is performed by the control unit.
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Citations (4)

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JPH01248070A (en) * 1988-03-30 1989-10-03 Hitachi Ltd Apparatus for testing semiconductor device
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JP2009168562A (en) * 2008-01-15 2009-07-30 Fujitsu Ltd Stress evaluating method using raman spectroscopy, and method of manufacturing semiconductor device
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Publication number Priority date Publication date Assignee Title
JPH01248070A (en) * 1988-03-30 1989-10-03 Hitachi Ltd Apparatus for testing semiconductor device
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JP2009168562A (en) * 2008-01-15 2009-07-30 Fujitsu Ltd Stress evaluating method using raman spectroscopy, and method of manufacturing semiconductor device
JP2017040543A (en) * 2015-08-19 2017-02-23 富士通株式会社 Method and system

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