JP2011075495A - Measurement control circuit device for measuring surface shape of sample by stylus type step profiler - Google Patents

Measurement control circuit device for measuring surface shape of sample by stylus type step profiler Download PDF

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JP2011075495A
JP2011075495A JP2009229525A JP2009229525A JP2011075495A JP 2011075495 A JP2011075495 A JP 2011075495A JP 2009229525 A JP2009229525 A JP 2009229525A JP 2009229525 A JP2009229525 A JP 2009229525A JP 2011075495 A JP2011075495 A JP 2011075495A
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differential transformer
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JP5544137B2 (en
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Naoki Mizutani
直樹 水谷
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Ulvac Inc
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, low-cost measurement control circuit device capable of minimizing jumping of a needle of a stylus type step profiler. <P>SOLUTION: The measurement control circuit device for measuring a surface shape of a sample by the stylus type step profiler provided with a probe movable not only vertically to a surface of a measurement object sample, but relatively along the surface of the measurement object sample, a needle pressure application means for exerting to the probe a needle pressure vertically applied to the surface of the measurement object sample, a differential transformer detecting a vertical displacement of the probe, and a control means for increasing/decreasing the needle pressure of the probe by detecting the jumping of the probe based on an output signal of the differential transformer and controlling the needle pressure application means according to detection of the jumping of the probe; includes a digital signal processor forming a reference signal by phase adjustment of a signal having the same frequency as a primary voltage to be applied to the primary side of the differential transformer, multiplying this reference signal by a signal detected from the secondary side of the differential transformer detecting a vertical displacement of the probe, and generating a signal indicating a vertical displacement value of the probe; and a circuit generating a control signal which controls a current value of a force generating coil of the needle pressure application means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、触針式段差計による試料の表面形状の測定用の計測制御回路装置に関するものである。一層特に、本発明は触針式段差計の針のとびを小さくする計測制御回路装置に関する。   The present invention relates to a measurement control circuit device for measuring the surface shape of a sample by a stylus type step meter. More particularly, the present invention relates to a measurement control circuit device for reducing the skip of a stylus type step meter.

本明細書において、用語“試料の表面形状”は試料の段差、膜厚、表面粗さの概念を包含するものとする。   In this specification, the term “sample surface shape” includes the concept of the step, film thickness, and surface roughness of the sample.

この種の触針式段差計の例としては、特許文献1及び特許文献2に記載されているものを挙げることができる。   Examples of this type of stylus type step meter include those described in Patent Document 1 and Patent Document 2.

添付図面の図1には、特許文献1及び特許文献2に記載された触針式段差計の例を示している。図1において、1は固定支持台で、その上に支点2を介して揺動支持棒3が設けられ、この揺動支持棒3の一端には探針4が下向きに取り付けられている。探針4はその先端はダイヤモンドで構成され、また先端の半径は一般的には2.5μmであるが、それより大きくても小さくてもよい。また、揺動支持棒3の他端には探針4に垂直下方の力すなわち針圧を加える力を発生する針圧付加手段5が設けられている。この針圧付加手段5は図示例では、揺動支持棒3の他端から上方へのびる作動子5aと作動子5aを受ける穴をもつコイル5bとで構成されている。揺動支持棒3の一端における探針4より支点2側において、探針4の垂直方向の変位を検出する検出手段6が設けられ、この検出手段6は揺動支持棒3に一端を固定した測定子6aと測定子6aの他端すなわち自由端を受けるコイル6bとを備えた差動トランスで構成されている。   FIG. 1 of the accompanying drawings shows an example of a stylus type step meter described in Patent Document 1 and Patent Document 2. In FIG. 1, reference numeral 1 denotes a fixed support base, on which a swing support bar 3 is provided via a fulcrum 2, and a probe 4 is attached to one end of the swing support bar 3 downward. The tip of the probe 4 is made of diamond, and the radius of the tip is generally 2.5 μm, but it may be larger or smaller. Further, the other end of the swing support bar 3 is provided with a needle pressure applying means 5 for generating a vertically downward force, ie, a force for applying a needle pressure to the probe 4. In the illustrated example, the needle pressure applying means 5 is composed of an actuator 5a extending upward from the other end of the swing support rod 3 and a coil 5b having a hole for receiving the actuator 5a. On the fulcrum 2 side of the probe 4 at one end of the swing support rod 3, a detection means 6 for detecting the vertical displacement of the probe 4 is provided. This detection means 6 has one end fixed to the swing support rod 3. The measuring element 6a and the other end of the measuring element 6a, that is, a coil 6b that receives the free end, are configured as a differential transformer.

また、図1において7は試料ホルダーで、その上に走査ステージ8が探針4に対して予定の操作速度で移動できるように設けられ、この走査ステージ8上には被測定試料9が取り付けられ得る。   In FIG. 1, reference numeral 7 denotes a sample holder, on which a scanning stage 8 is provided so as to be movable at a predetermined operation speed with respect to the probe 4, and a sample 9 to be measured is attached on the scanning stage 8. obtain.

針圧付加手段5及び探針4の垂直方向の変位を検出する検出手段6は図2及び図3に示すような制御手段に接続され、この制御手段は検出手段6からの出力信号に基いて針圧付加手段5の動作を制御するように構成されている。なお、図1の装置において試料9を固定して探針側を走査するように構成することも可能である。   The detecting means 6 for detecting the displacement in the vertical direction of the needle pressure applying means 5 and the probe 4 is connected to a control means as shown in FIGS. 2 and 3, and this control means is based on an output signal from the detecting means 6. The operation of the needle pressure applying means 5 is configured to be controlled. In the apparatus shown in FIG. 1, the sample 9 can be fixed and the probe side can be scanned.

図1に示す制御手段の構成の一例(特許文献2)を図11に示し、図11において、11はコンピュータ装置で、このコンピュータ装置11はアナログ入出力ボード12を介して、針圧発生装置5におけるコイル5bに接続された針圧発生装置用電源13及び走査ステージ8の駆動装置14にそれぞれ接続されている。また、コンピュータ装置11は、汎用インターフェースボード15を介してデジタルロックイン増幅器及び発振器を備えた検出回路16に接続され、この検出回路16は変位センサ6を成す差動トランスの一次コイル及び二次コイルに接続されている。   An example of the configuration of the control means shown in FIG. 1 (Patent Document 2) is shown in FIG. 11. In FIG. 11, 11 is a computer device, and this computer device 11 is connected to the needle pressure generator 5 via an analog input / output board 12. Are connected to the power source 13 for the needle pressure generator connected to the coil 5b and the driving device 14 of the scanning stage 8 respectively. Further, the computer device 11 is connected to a detection circuit 16 having a digital lock-in amplifier and an oscillator via a general-purpose interface board 15, and the detection circuit 16 is a primary coil and a secondary coil of a differential transformer constituting the displacement sensor 6. It is connected to the.

雑音を減らすために変位センサ6からの出力信号即ち測定データは、デジタルロックイン増幅器及び発振器を備えた検出回路16における低域通過フィルタ(LPF)に通され、高い周波数の雑音は低減される。コンピュータ装置11は、送られてきたデータをソフトのフィルタ、即ち、デジタルフィルタで同様のLPF処理をしてもよい。この処理は、計算によって高い周波数の雑音を低減する方法である。このようにして、それらのLPF処理によって高い周波数成分の雑音が除去され、雑音の小さい表面形状データが得られる。   In order to reduce the noise, the output signal from the displacement sensor 6, i.e. the measurement data, is passed through a low-pass filter (LPF) in a detection circuit 16 equipped with a digital lock-in amplifier and an oscillator to reduce high frequency noise. The computer apparatus 11 may perform the same LPF processing on the transmitted data with a soft filter, that is, a digital filter. This process is a method of reducing high frequency noise by calculation. In this manner, high frequency component noise is removed by the LPF processing, and surface shape data with low noise is obtained.

ところで、半導体素子を作製する際のSi基板や液晶パネル製作時のガラス基板上の薄膜プロセスにおける段差などの形状測定では、探針4を被測定試料9に対して相対的に一定の速さで掃引し、差動トランス等の変位センサ6の出力電圧を一定の時間間隔で計測器により測定し、そのデータがコンピュータ装置11に送られ、モニターに表示される。ここで探針4の被測定試料9への力が0.1mgfと小さいときには、走査速度が大きいと段差の箇所で探針4が跳び上がる場合がある。   By the way, in shape measurement such as a step in a thin film process on a glass substrate at the time of manufacturing a semiconductor element or a liquid crystal panel, the probe 4 is moved at a constant speed relative to the sample 9 to be measured. The output voltage of the displacement sensor 6 such as a differential transformer is measured by a measuring instrument at regular time intervals, and the data is sent to the computer device 11 and displayed on the monitor. Here, when the force of the probe 4 on the sample 9 to be measured is as small as 0.1 mgf, the probe 4 may jump up at the level difference when the scanning speed is large.

それを抑えるために、探針4の位置zを常にモニターし、力発生コイル5bに流す電流を制御するようにした制御装置の例(特許文献1)が図12に示されている。
参照)(特許文献1)。
FIG. 12 shows an example of a control device (Patent Document 1) that constantly monitors the position z of the probe 4 and controls the current flowing through the force generating coil 5b in order to suppress this.
(See Patent Document 1).

図12に示す針とび抑制制御を行うための計測制御系の構成例では、差動トランス等から成り得る検出手段即ち変位センサ6は探針4の垂直方向の位置zを測定し、変位センサ6の出力はロックインアンプ等の計測器21で計測される。計測器21は計測した探針の変位信号をアナログ信号としてアナログ入出力ボード22へ出力する。このアナログ入出力ボード22は、リアルタイムOSで動作するコントローラ23で制御され、計測器21からのアナログ信号取り込む。コントローラ23のCPU及びそれにLANを介し接続されたコンピュータ装置24でその信号を探針4の垂直方向の変位zに換算し、その時間微分dz/dt即ち探針の変位速度v及び2階微分dz/dt即ち探針の加速度αを計算し、それら値から探針のとびを判断するように機能する。コントローラ23において探針4のとびが検知されると、探針4の針圧を増すために、針圧付加手段5(図1)におけるコイル5bに流す電流を増すようにする。すなわちアナログ入出力ボード22を介して、コイル5bに流す電流を制御するアナログ電圧信号がコイル5bに接続された電源25に供給され、この電源25を制御する。 In the configuration example of the measurement control system for performing the needle jump suppression control shown in FIG. 12, the detection means, that is, the displacement sensor 6, which can be a differential transformer, measures the vertical position z of the probe 4, and the displacement sensor 6 Is measured by a measuring instrument 21 such as a lock-in amplifier. The measuring instrument 21 outputs the measured probe displacement signal to the analog input / output board 22 as an analog signal. The analog input / output board 22 is controlled by a controller 23 that operates with a real-time OS, and takes in an analog signal from the measuring instrument 21. The signal is converted into the vertical displacement z of the probe 4 by the CPU of the controller 23 and the computer device 24 connected thereto via the LAN, and the time differential dz / dt, ie, the probe displacement speed v and the second-order differential d. 2 z / dt 2, that is, the acceleration α of the probe is calculated, and it functions to determine the skip of the probe from those values. When a jump of the probe 4 is detected by the controller 23, in order to increase the needle pressure of the probe 4, the current flowing through the coil 5b in the needle pressure applying means 5 (FIG. 1) is increased. That is, an analog voltage signal for controlling a current flowing through the coil 5b is supplied to the power source 25 connected to the coil 5b via the analog input / output board 22, and the power source 25 is controlled.

計測器21によって測定した探針4の垂直方向の位置zの信号は、別個に設けた制御器に送られて、そこで別の計算処理を行い、力用コイルに流す電流値を算出し、制御することで探針のとびを小さくするようにされてきた(特許文献1)。     The signal of the position 4 in the vertical direction of the probe 4 measured by the measuring instrument 21 is sent to a separately provided controller, where another calculation process is performed to calculate the value of the current flowing through the force coil, and control By doing so, the skip of the probe has been made small (Patent Document 1).

特開2009−20050JP2009-20050 特開2009−133730JP 2009-133730 A

前述のように先行技術においては、針のとびを抑制するには、計測器の他に専用の制御器が必要であり、装置としてのコストが上がり、計測制御器として小型化ができないという問題がある。   As described above, in the prior art, in order to suppress needle skipping, a dedicated controller is required in addition to the measuring instrument, which increases the cost of the device and makes it impossible to downsize the measuring controller. is there.

そこで、本発明は、小型化、コストダウンができる、触針式段差計の針のとびを小さくする計測制御回路装置を提供することを目的としている。   SUMMARY OF THE INVENTION An object of the present invention is to provide a measurement control circuit device that can reduce the size of the stylus type step meter and reduce the cost of the needle.

本発明によれば、被測定試料の表面に対して垂直方向に移動可能でしかも被測定試料の表面に沿って相対的に移動可能である探針と、
探針に被測定試料の表面に対して垂直方向に向う針圧を作用させる針圧付加手段と、
探針の垂直方向の変位を検出する差動トランスと、
差動トランスの出力信号に基き探針のとびを検出すると共に探針のとびの検出に応じて針圧付加手段を制御して探針の針圧を増減する制御手段と
を有する触針式段差計による試料の表面形状の測定用の計測制御回路装置において、
差動トランスの一次側に印加される一次電圧と同じ周波数の信号を位相調整して参照信号を形成し、この参照信号と探針の垂直方向の変位を検出する差動トランスの二次側からの検出した信号とを掛算処理し、探針の垂直方向の変位値を表す信号を発生するデジタル信号処理装置と、
針圧付加手段の力発生用コイルの電流値を制御する制御信号を発生する回路と
を有することを特徴としている。
According to the present invention, a probe that is movable in a direction perpendicular to the surface of the sample to be measured and is relatively movable along the surface of the sample to be measured;
Needle pressure application means for applying a needle pressure in the direction perpendicular to the surface of the sample to be measured to the probe;
A differential transformer for detecting the vertical displacement of the probe;
A stylus type step having a control means for detecting a probe jump based on an output signal of the differential transformer and controlling a needle pressure applying means in accordance with the detection of the probe jump to increase or decrease the needle pressure of the probe. In the measurement control circuit device for measuring the surface shape of the sample with a meter,
A reference signal is formed by phase-adjusting a signal having the same frequency as the primary voltage applied to the primary side of the differential transformer, and from the secondary side of the differential transformer that detects the vertical displacement of the reference signal and the probe. A digital signal processing device that multiplies the detected signal and generates a signal that represents the vertical displacement value of the probe;
And a circuit for generating a control signal for controlling the current value of the force generating coil of the needle pressure applying means.

デジタル信号処理装置は、sin波を発生するsin波発生回路と、sin波発生回路で発生したsin波を振幅調整する振幅調整回路とを備え、差動トランスの一次側に印加される一次電圧を出力するように構成され得る。   The digital signal processing apparatus includes a sine wave generation circuit that generates a sine wave and an amplitude adjustment circuit that adjusts the amplitude of the sine wave generated by the sine wave generation circuit, and a primary voltage applied to a primary side of the differential transformer. It can be configured to output.

デジタル信号処理装置は、さらに、sin波発生回路で発生したsin波を振幅及び位相調整して参照信号を発生する振幅・位相調整回路を備え得る。   The digital signal processing apparatus may further include an amplitude / phase adjustment circuit that generates a reference signal by adjusting the amplitude and phase of the sine wave generated by the sine wave generation circuit.

参照信号は、差動トランスの一次側に印加される一次電圧と同じ周波数で位相を調整された信号であり得る。   The reference signal may be a signal whose phase is adjusted at the same frequency as the primary voltage applied to the primary side of the differential transformer.

参照信号を発生する振幅・位相調整回路は、外部発信器より差動トランスの一次側に印加される一次電圧から分岐した電圧を受け、振幅及び位相調整して参照信号を発生するように構成され得る。   The amplitude / phase adjustment circuit for generating the reference signal is configured to receive a voltage branched from the primary voltage applied to the primary side of the differential transformer from the external transmitter, and generate the reference signal by adjusting the amplitude and phase. obtain.

デジタル信号処理装置は、参照信号と差動トランスの二次側に発生した測定信号とを掛算する掛算回路と、掛算回路からの信号をフィルタリング処理して、雑音を含む測定信号の中から参照信号と同じ周波数成分を取り出す低域通過フィルタ回路とを備え、算出した測定信号の振幅及び位相に基き、差動トランスのコアの変位を求めるように構成されたデジタルロックイン増幅器から成り得る。   The digital signal processing device multiplies the reference signal and the measurement signal generated on the secondary side of the differential transformer, and performs filtering processing on the signal from the multiplication circuit to generate the reference signal from the measurement signal including noise. And a low-pass filter circuit for extracting the same frequency component, and a digital lock-in amplifier configured to obtain the displacement of the core of the differential transformer based on the calculated amplitude and phase of the measurement signal.

デジタルロックイン増幅器は、1周期の1/4ずれた時点での参照信号の値を用いて測定信号のcos成分とsin成分とを同時に得るように構成され得る。   The digital lock-in amplifier can be configured to simultaneously obtain the cos component and the sin component of the measurement signal using the value of the reference signal at a point shifted by ¼ of one cycle.

差動トランスの一次側に印加されるsin波の一次電圧の周波数は5kHzであり、差動トランスの二次コイルに発生する二次電圧を200kS/sでAD変換して読み込み、5μs毎に計算処理するように構成され得る。   The frequency of the sin wave primary voltage applied to the primary side of the differential transformer is 5 kHz, and the secondary voltage generated in the secondary coil of the differential transformer is AD-converted at 200 kS / s and read every 5 μs. It can be configured to process.

デジタル信号処理装置は、算出した測定信号の振幅及び位相に基き、針圧付加手段の力発生用コイルの電流値を制御するように構成され得る。   The digital signal processing device can be configured to control the current value of the force generating coil of the needle pressure applying means based on the calculated amplitude and phase of the measurement signal.

本発明によれば、触針式段差計の計測回路としてデジタルシグナル処理装置(DSP)を用いて、差動トランスの出力を計測し、その値を計算処理して、針圧付加手段の力発生用コイルの電流値を制御することにより、別個に制御装置を設ける必要がなく、装置のコストを低減でき、触針式段差計による試料の表面形状の測定用の計測制御回路装置計測制御器として小型化できる。また一つのデジタルシグナル処理装置(DSP)で探針の変位計測と針圧付加手段の力の制御の両方が可能となり、計測装置と制御装置をそれぞれ設ける必要がなく、探針のとびを小さくすることができる小型で安価な計測制御回路装置を提供できる。   According to the present invention, a digital signal processing device (DSP) is used as a measuring circuit for a stylus step meter, and the output of a differential transformer is measured, and the value is calculated and processed to generate force of the needle pressure applying means. By controlling the current value of the coil, it is not necessary to provide a separate control device, the cost of the device can be reduced, and as a measurement control circuit device measurement controller for measuring the surface shape of the sample with a stylus profilometer Can be downsized. In addition, one digital signal processing device (DSP) can both measure the displacement of the probe and control the force of the needle pressure applying means, so that it is not necessary to provide a measuring device and a control device, and the probe skip is reduced. Thus, a small and inexpensive measurement control circuit device can be provided.

差動トランスの二次側に発生する二次電圧(測定信号)の振幅と位相は、差動トランスの一次側に印加される一次電圧を参照信号として用いて、計算処理のみにより求めることができる。また、差動トランスの調整時に行う必要のある参照信号の位相のシフトも、ハードウエアとしての移相器を必要とせずに、計算処理のみで行うことができ、その結果、装置を低コストで、小型化して提供することができる。   The amplitude and phase of the secondary voltage (measurement signal) generated on the secondary side of the differential transformer can be obtained only by calculation processing using the primary voltage applied to the primary side of the differential transformer as a reference signal. . In addition, the phase shift of the reference signal, which must be performed when adjusting the differential transformer, can be performed only by calculation processing without the need for a phase shifter as hardware. Can be provided in a smaller size.

一つのデジタルシグナル処理装置(DSP)が一次電圧用の発振器、ロックインアンプの計測器、力発生用電流の制御器の機能を兼ね備えているので、小型化、コストダウンができる。   One digital signal processing device (DSP) combines the functions of an oscillator for primary voltage, a measuring instrument for lock-in amplifiers, and a controller for current generation for force generation, so that the size and cost can be reduced.

参照信号を外部から取る場合に、参照信号の位相を変化したときの結果を計算で求める際に必要な、過去の参照信号電圧値Rsを保持するのに、リングバッファメモリを用いた場合には、演算時間の無駄やデジタルシグナル処理装置(DSP)の処理の負担が軽減される。   When using a ring buffer memory to hold the past reference signal voltage value Rs necessary for calculating the result when the phase of the reference signal is changed when obtaining the reference signal from the outside , Waste of computation time and processing load of the digital signal processing device (DSP) are reduced.

本発明が適用される接触式段差計の構成を示す概略部分断面図。The schematic fragmentary sectional view which shows the structure of the contact-type level difference meter to which this invention is applied. 本発明の一実施形態による計測制御回路装置の構成を示すブロック線図。The block diagram which shows the structure of the measurement control circuit apparatus by one Embodiment of this invention. 図2の計測制御回路装置におけるデジタルシグナル処理装置(DSP)の構成を示すブロック線図。The block diagram which shows the structure of the digital signal processing apparatus (DSP) in the measurement control circuit apparatus of FIG. 本発明の変形例を示すブロック線図。The block diagram which shows the modification of this invention. 図4の計測制御回路装置におけるデジタルシグナル処理装置(DSP)の構成を示すブロック線図。The block diagram which shows the structure of the digital signal processing apparatus (DSP) in the measurement control circuit apparatus of FIG. 参照信号の位相変化の一例を示すグラフ。The graph which shows an example of the phase change of a reference signal. 参照信号の位相変化の別の例を示すグラフ。The graph which shows another example of the phase change of a reference signal. 参照信号Rc、Rsの取り方の例を示すグラフ。The graph which shows the example of how to take reference signal Rc, Rs. 本発明による装置を用いて測定した測定結果の一例を示すグラフ。The graph which shows an example of the measurement result measured using the apparatus by this invention. 本発明による装置を用いて測定した測定結果の別の例を示すグラフ。The graph which shows another example of the measurement result measured using the apparatus by this invention. 先行技術による接触式段差計用の計測・制御系の構成を示すブロック線図。The block diagram which shows the structure of the measurement and control system for the contact-type level difference meter by a prior art. 先行技術による接触式段差計用の別の計測・制御系の構成を示すブロック線図。The block diagram which shows the structure of another measurement and control system for the contact-type level difference meter by a prior art.

以下添付図面の図2〜図10を参照して本発明の実施形態について説明する。   Embodiments of the present invention will be described below with reference to FIGS.

図2には、本発明の計測制御回路装置の一つの実施形態をブロック線図で示し、30は本発明の計測制御回路装置であり、計測制御回路装置30はデジタルシグナル処理装置(DSP)31と、アナログ−デジタル変換器32a及び複数のデジタル−アナログ変換器32b、32c、32dを備えた変換回路32と、低域通過フィルタ(LPF)33と、前置増幅器34と、電圧−電流変換回路35とを有している。デジタルシグナル処理装置(DSP)31は例えばテキサスインスツルメンツ社製のモデルC6713で構成され得る。36は図1に示すような触針式段差計のセンサヘッドであり、センサヘッド36は、一次コイル、二次コイル及び測定子を成すコアを備えた差動トランス37と、触針式段差計の探針4に垂直下方の力すなわち針圧を加える力を発生する針圧付加手段の力発生用コイル38とを有している。また39は設定、表示用のコンピュータである。デジタルシグナル処理装置(DSP)31は、変換回路32におけるアナログ−デジタル変換器32a、低域フィルタ(LPF)33及び前置増幅器34を介して差動トランス37の二次コイルに接続され、この二次コイルからの測定信号Sを受けるようにされている。またデジタルシグナル処理装置(DSP)31は、変換回路32におけるデジタル−アナログ変換器32b及び電圧−電流変換回路35を介して針圧付加手段の力発生用コイル38に接続されている。さらにデジタルシグナル処理装置(DSP)31は、RS−232Cシリアル通信系を介して設定、表示用のコンピュータ39に接続されている。また変換回路32におけるデジタル−アナログ変換器32dも設定、表示用のコンピュータ39に接続されている。   FIG. 2 is a block diagram showing one embodiment of the measurement control circuit device of the present invention, in which 30 is the measurement control circuit device of the present invention, and the measurement control circuit device 30 is a digital signal processing device (DSP) 31. A conversion circuit 32 including an analog-digital converter 32a and a plurality of digital-analog converters 32b, 32c, 32d, a low-pass filter (LPF) 33, a preamplifier 34, and a voltage-current conversion circuit. 35. The digital signal processing device (DSP) 31 can be configured by, for example, a model C6713 manufactured by Texas Instruments. 36 is a sensor head of a stylus step meter as shown in FIG. 1. The sensor head 36 includes a differential transformer 37 having a primary coil, a secondary coil, and a core constituting a measuring element, and a stylus step meter. And a force generating coil 38 of a needle pressure applying means for generating a force for applying a vertically downward force, that is, a force for applying a needle pressure to the probe 4. Reference numeral 39 denotes a setting / display computer. A digital signal processing device (DSP) 31 is connected to a secondary coil of a differential transformer 37 through an analog-digital converter 32a, a low-pass filter (LPF) 33, and a preamplifier 34 in a conversion circuit 32. The measurement signal S from the next coil is received. The digital signal processing device (DSP) 31 is connected to the force generating coil 38 of the needle pressure applying means via the digital-analog converter 32 b and the voltage-current conversion circuit 35 in the conversion circuit 32. Further, the digital signal processing device (DSP) 31 is connected to a computer 39 for setting and display via an RS-232C serial communication system. A digital-analog converter 32d in the conversion circuit 32 is also connected to a computer 39 for setting and display.

図3を参照してデジタルシグナル処理装置(DSP)31についてさらに説明すると、図示デジタルシグナル処理装置(DSP)31は、sin波を発生するsin波発生回路31aと、sin波発生回路31aで発生したsin波を振幅調整する振幅調整回路31bと、sin波発生回路31aで発生したsin波を振幅及び位相調整して参照信号を発生する振幅・位相調整回路31cと、振幅・位相調整回路31cで形成された参照信号と差動トランス37の二次コイル37bに発生した二次電圧である測定すべき信号とを掛算する掛算回路31dと、低域通過フィルタ31eとを備えている。振幅調整回路31bはデジタル−アナログ変換器32cに接続され、デジタル−アナログ変換器32cは上述のように差動トランス37の二次コイル37aに一次電圧を印加するようにされている。   The digital signal processing device (DSP) 31 will be further described with reference to FIG. 3. The illustrated digital signal processing device (DSP) 31 is generated by a sine wave generation circuit 31a that generates a sine wave and a sine wave generation circuit 31a. An amplitude adjustment circuit 31b that adjusts the amplitude of the sine wave, an amplitude / phase adjustment circuit 31c that generates a reference signal by adjusting the amplitude and phase of the sine wave generated by the sine wave generation circuit 31a, and an amplitude / phase adjustment circuit 31c. A multiplication circuit 31d that multiplies the reference signal and the signal to be measured, which is a secondary voltage generated in the secondary coil 37b of the differential transformer 37, and a low-pass filter 31e. The amplitude adjustment circuit 31b is connected to a digital-analog converter 32c, and the digital-analog converter 32c applies a primary voltage to the secondary coil 37a of the differential transformer 37 as described above.

このように構成した図示計測制御回路装置の動作について図6〜図8を参照しながら説明する。
センサヘッド36の差動トランス37の二次コイルに発生した二次電圧は測定信号として前置増幅器34で100倍程度増幅され、アンチエイリアシングフィルタ(LPF)33(例えばカットオフ周波数10kHz)を通してアナログ−デジタル変換器32aでデジタル信号に変換され、デジタルシグナル処理装置(DSP)31に送られる。差動トランス37の一次コイル37aには、デジタルシグナル処理装置(DSP)31においてsin波発生回路31aにより例えば5kHzのsin波を発生し、デジタル−アナログ変換器32bでアナログ電圧に変換して供給される。電流が足らなければ変換回路32における演算増幅器(図示していない)で電流増幅すればよい。
The operation of the illustrated measurement control circuit device configured as described above will be described with reference to FIGS.
The secondary voltage generated in the secondary coil of the differential transformer 37 of the sensor head 36 is amplified about 100 times by the preamplifier 34 as a measurement signal, and analog-through the anti-aliasing filter (LPF) 33 (for example, cutoff frequency 10 kHz). The digital signal is converted into a digital signal by a digital converter 32 a and sent to a digital signal processor (DSP) 31. For example, a 5 kHz sine wave is generated by a sine wave generation circuit 31a in a digital signal processing device (DSP) 31 in the digital coil 37a of the differential transformer 37, and converted into an analog voltage by a digital-analog converter 32b. The If the current is not sufficient, the current may be amplified by an operational amplifier (not shown) in the conversion circuit 32.

デジタルシグナル処理装置(DSP)31による差動トランス37のコアの変位すなわち探針の垂直方向の変位zの測定について説明する。
差動トランス37の二次コイル37bに発生した二次電圧に相当する測定信号Sと差動トランス37の一次コイル37aへの電圧に相当する参照信号Rc、 Rs(互いに位相が90度ずれている。図6参照)の“積の時間平均”は以下のようになる。ここで
測定信号S =asin(ωt+φ)
参照信号Rc=2sinωt
測定信号S・参照信号Rcの時間平均=acosφ
参照信号Rs=2cosωt=2sin(ωt+π/2)
測定信号S・参照信号Rsの時間平均=asinφ
これら信号はロックインアンプで計測される。測定信号の振幅が直接出るように、参照信号は規格化される。すなわち、これら信号は振幅と位相情報を含んでおり、差動トランス37のコアの変位が十分大きい時にはφを0に設定すれば、a cosφは差動トランス37のコアの変位zに比例する。
差動トランス37のコアの変位が十分に大きい(例えば1mm)時には、例えば以下に記載するように処理される。通常、それぞれの位相も位相差も分からない。
差動トランス37のコアの変位が1mmの時
測定信号S =asin(ωt+α)
参照信号Rc=2sin(ωt+θ)
測定信号S・参照信号Rcの時間平均=acos(α−θ) (1)
参照信号Rs=2cos(ωt+θ)
測定信号S・参照信号Rsの時間平均=asin(α−θ) (2)
ここで、測定信号S・参照信号Rcの時間平均が最大となり、測定信号S・参照信号Rsの時間平均がゼロとなるように、θを設定すれば(θ→α)、式(1)が差動トランス37のコアの変位zに比例することになり、変位センサになり得る。
The measurement of the displacement of the core of the differential transformer 37, that is, the displacement z in the vertical direction of the probe, by the digital signal processing device (DSP) 31 will be described.
The measurement signal S corresponding to the secondary voltage generated in the secondary coil 37b of the differential transformer 37 and the reference signals Rc and Rs corresponding to the voltage to the primary coil 37a of the differential transformer 37 (the phases are shifted by 90 degrees from each other). (Refer to FIG. 6) “Time average of product” is as follows. Where measurement signal S = asin (ωt + φ)
Reference signal Rc = 2 sin ωt
Time average of measurement signal S and reference signal Rc = acosφ
Reference signal Rs = 2 cos ωt = 2 sin (ωt + π / 2)
Time average of measurement signal S and reference signal Rs = asinφ
These signals are measured by a lock-in amplifier. The reference signal is normalized so that the amplitude of the measurement signal is directly output. That is, these signals include amplitude and phase information. If φ is set to 0 when the core displacement of the differential transformer 37 is sufficiently large, a cos φ is proportional to the core displacement z of the differential transformer 37.
When the displacement of the core of the differential transformer 37 is sufficiently large (for example, 1 mm), the processing is performed as described below, for example. Normally, neither phase nor phase difference is known.
When the displacement of the core of the differential transformer 37 is 1 mm Measurement signal S = asin (ωt + α)
Reference signal Rc = 2 sin (ωt + θ)
Time average of measurement signal S and reference signal Rc = acos (α−θ) (1)
Reference signal Rs = 2 cos (ωt + θ)
Time average of measurement signal S and reference signal Rs = asin (α−θ) (2)
If θ is set so that the time average of the measurement signal S and the reference signal Rc is maximized and the time average of the measurement signal S and the reference signal Rs is zero (θ → α), the equation (1) is obtained. This is proportional to the displacement z of the core of the differential transformer 37 and can be a displacement sensor.

デジタルシグナル処理装置(DSP)31におけるAD、DA変換は例えば200kS/sで行い、5μsごとにデジタルシグナル処理装置(DSP)31で計算処理をすればよい。ロックインアンプとしてのデジタルシグナル処理装置(DSP)31における処理内容は前述のとおりで、測定信号と参照信号(差動トランス37の一次コイル37aへのsin波の電圧信号の位相をプログラム内で変えることにより生成され得る)を掛け算してデジタルフィルタのLPF(例えばカットオフ周波数20Hz)すなわち図3の低域通過フィルタ31eに通せばよい。針とび抑制のアルゴリズムで速い応答が必要である場合には、カットオフ周波数は数100Hzにすればよい。センサコアすなわち差動トランス37のコアが1mm付近で参照信号と測定信号の位相差を0にしておけば、前述の掛け算、LPFの計算結果が差動トランス37のコアの変位に比例し、係数を掛ければ、差動トランス37のコアの変位になる。   The AD and DA conversion in the digital signal processing device (DSP) 31 is performed at 200 kS / s, for example, and the digital signal processing device (DSP) 31 may perform calculation processing every 5 μs. The processing contents in the digital signal processing device (DSP) 31 as the lock-in amplifier are as described above, and the phase of the measurement signal and the reference signal (the sin wave voltage signal to the primary coil 37a of the differential transformer 37 is changed in the program. 3) may be multiplied by the digital filter LPF (for example, a cutoff frequency of 20 Hz), that is, the low-pass filter 31e of FIG. When a fast response is required by the needle jump suppression algorithm, the cut-off frequency may be several hundred Hz. If the sensor core, that is, the core of the differential transformer 37 is near 1 mm and the phase difference between the reference signal and the measurement signal is set to 0, the calculation result of the multiplication and the LPF is proportional to the displacement of the core of the differential transformer 37, and the coefficient is When applied, the core of the differential transformer 37 is displaced.

差動トランス37のコアの変位をデジタルシグナル処理装置(DSP)31において5μsごとにモニターして、特許文献1に記載のアルゴリズムの制御を行えば、針とびの抑制制御ができる。針圧付加手段38への電流は、デジタルシグナル処理装置(DSP)31から出力に応じて変換回路32におけるデジタル−アナログ変換器32bにおいてアナログ電圧を作り、このアナログ電圧を電圧−電流変換回路35において電流に変換し、針圧付加手段の力発生コイル38へ供給される。   If the displacement of the core of the differential transformer 37 is monitored every 5 μs in the digital signal processor (DSP) 31 and the algorithm described in Patent Document 1 is controlled, the needle jump suppression control can be performed. The current to the needle pressure applying means 38 is made an analog voltage in the digital-analog converter 32b in the conversion circuit 32 according to the output from the digital signal processing device (DSP) 31, and this analog voltage is generated in the voltage-current conversion circuit 35. It is converted into an electric current and supplied to the force generating coil 38 of the needle pressure applying means.

次に、図4及び図5を参照して本発明の変形実施形態について説明する。図4及び図5において、図2及び図3に示す構成要素に対応する部分は同じ番号で示す。この場合には、差動トランス37の一次コイルへの5kHzのsin波の電圧は外部発振器40で発生される。外部発振器40で発生された5kHzのsin波は図5に示すように分岐されてデジタルロックイン増幅器の振幅・位相調整回路31cへ送られ、振幅及び位相調整されて参照信号が形成される。この参照信号は、アンチエイリアシングフィルタすなわち低域フィルタ41を通して変換回路32におけるアナログ−デジタル変換器32eでデジタル信号に変換され、デジタルシグナル処理装置(DSP)31に送られる。すなわち参照信号は掛算回路31dへ供給される。そして図3に示すと同様に処理される。   Next, a modified embodiment of the present invention will be described with reference to FIGS. 4 and 5, portions corresponding to the components shown in FIGS. 2 and 3 are denoted by the same numbers. In this case, a 5 kHz sine wave voltage to the primary coil of the differential transformer 37 is generated by the external oscillator 40. The 5 kHz sine wave generated by the external oscillator 40 is branched as shown in FIG. 5 and sent to the amplitude / phase adjustment circuit 31c of the digital lock-in amplifier, where the reference signal is formed by adjusting the amplitude and phase. This reference signal is converted into a digital signal by an analog-digital converter 32e in the conversion circuit 32 through an anti-aliasing filter or low-pass filter 41 and sent to a digital signal processing device (DSP) 31. That is, the reference signal is supplied to the multiplication circuit 31d. Then, the processing is performed as shown in FIG.

図4及び図5に示す例はデジタルロックインアンプとしての動作例である。外部発振器40から差動トランス37の一次コイルへ5kHz, 1Vrmsの電圧を印加し、それにより差動トランス37の二次コイルに発生した測定信号としての電圧は前置増幅器34で100倍に増幅される。こうして前置増幅器34で増幅された測定信号及び外部発振器39から差動トランス37の一次コイルへ印加される電圧の参照信号は、それぞれ、カットオフ周波数10kHzの低域通過フィルタ33及びバタワース4次型の低域通過フィルタ41に通されて、エイリアシングによる雑音の発生原因となる高周波成分をカットされ、そして変換回路32へ送られる。変換回路32では、測定信号及び参照信号は、それぞれアナログ−デジタル変換器32a、32eにより200kS/sで同時にAD変換され、デジタルシグナル処理装置(DSP)31に送られる。図示例では、変換回路32における各アナログ−デジタル変換器及びデジタル−アナログ変換器としては分解能が16bitのものが用いられる。デジタルシグナル処理装置(DSP)31としては、テキサスインスツルメンツ社製のモデルC6713が用いられる。   The examples shown in FIGS. 4 and 5 are operation examples as a digital lock-in amplifier. A voltage of 5 kHz and 1 Vrms is applied from the external oscillator 40 to the primary coil of the differential transformer 37, whereby the voltage as a measurement signal generated in the secondary coil of the differential transformer 37 is amplified 100 times by the preamplifier 34. The The measurement signal amplified by the preamplifier 34 and the reference signal of the voltage applied from the external oscillator 39 to the primary coil of the differential transformer 37 are a low-pass filter 33 having a cutoff frequency of 10 kHz and a Butterworth fourth-order type, respectively. Is passed through the low-pass filter 41, and high-frequency components that cause noise due to aliasing are cut and sent to the conversion circuit 32. In the conversion circuit 32, the measurement signal and the reference signal are simultaneously AD-converted at 200 kS / s by analog-digital converters 32a and 32e, respectively, and sent to a digital signal processing device (DSP) 31. In the illustrated example, each analog-digital converter and digital-analog converter in the conversion circuit 32 has a resolution of 16 bits. As the digital signal processing device (DSP) 31, model C6713 manufactured by Texas Instruments is used.

次に、図示回路装置の動作について再び図6〜図8を参照しながら説明する。デジタルシグナル処理装置(DSP)31では、差動トランス37のコアの変位が求められ、また外部発振器40から取り込んだ参照信号の位相の変更が行われる。   Next, the operation of the illustrated circuit device will be described with reference to FIGS. 6 to 8 again. In the digital signal processor (DSP) 31, the displacement of the core of the differential transformer 37 is obtained, and the phase of the reference signal taken from the external oscillator 40 is changed.

通常はθ→αだが、それを行わないで差動トランス37のコアの変位zを求める方法について説明する。図4に示す回路装置において、参照信号は計算用にデジタルシグナル処理装置(DSP)31で作ることも考えられるが、外部発振器40からの信号と全く同じ周波数の信号を作ることは困難なので、外部信号を取り込んで利用するのが好ましい。   A method for obtaining the core displacement z of the differential transformer 37 without performing it is usually θ → α. In the circuit device shown in FIG. 4, it is conceivable that the reference signal is generated by the digital signal processing device (DSP) 31 for calculation, but it is difficult to generate a signal having exactly the same frequency as the signal from the external oscillator 40. It is preferable to capture and use the signal.

外部発振器40から読み込んだものを用いる場合、1周期を例えば40点で表わしているときには、位相を連続的に変化させることは簡単ではない。
差動トランス37のコアの変位が任意のとき、測定信号Sの振幅、位相は任意の値になっており、以下のように表すことができる。
差動トランス37におけるコアの変位が任意である時、測定信号Sの振幅及び位相が変化する。
測定信号S =bsin(ωt+β)
参照信号Rc=2sin(ωt+θ)
測定信号S・参照信号Rcの時間平均=bcos(β−θ) (3)
参照信号Rs=2cos(ωt+θ)
測定信号S・参照信号Rsの時間平均=bsin(β−θ) (4)
求めたいのはθをαに置き換えたbcos(β−α)であり、これが差動トランス37のコアの変位 z に比例する。これを書き換えると次のように表される。
bcos(β−α)=bcos(β−θ)cos(α−θ)
+bsin(β−θ)sin(α−θ)
=S・Rc・cos(α−θ)+S・Rs・sin(α−θ)の時間平均
つまり、bcos(β−α)は図4に示すように、参照信号の位相をα−θ増すことに相当する。従って、元々の参照信号の位相では、
S・Rcの時間平均=bcos(β−θ)
であり、参照信号の位相をφ増すと、
S・Rc・cosφ+S・Rs・sinφの時間平均=bcos(β−θ−φ)
(5)
となる。
これにより、参照信号の位相は任意に変えることができる。実際には、位相は変えていないが、変えた場合の“測定信号×参照信号の時間平均”の値がデジタルシグナル処理装置(DSP)31で算出され、出力される。
When using what is read from the external oscillator 40, it is not easy to change the phase continuously when one cycle is expressed by 40 points, for example.
When the displacement of the core of the differential transformer 37 is arbitrary, the amplitude and phase of the measurement signal S are arbitrary values, which can be expressed as follows.
When the displacement of the core in the differential transformer 37 is arbitrary, the amplitude and phase of the measurement signal S change.
Measurement signal S = bsin (ωt + β)
Reference signal Rc = 2 sin (ωt + θ)
Time average of measurement signal S and reference signal Rc = b cos (β−θ) (3)
Reference signal Rs = 2 cos (ωt + θ)
Time average of measurement signal S and reference signal Rs = bsin (β−θ) (4)
What is desired is bcos (β−α) in which θ is replaced with α, which is proportional to the displacement z of the core of the differential transformer 37. This can be rewritten as follows.
bcos (β−α) = bcos (β−θ) cos (α−θ)
+ Bsin (β−θ) sin (α−θ)
= S · Rc · cos (α−θ) + S · Rs · sin (α−θ) time average, that is, bcos (β−α) increases the phase of the reference signal by α−θ, as shown in FIG. It corresponds to. Therefore, in the phase of the original reference signal,
S · Rc time average = b cos (β−θ)
When the phase of the reference signal is increased by φ,
S · Rc · cosφ + S · Rs · sinφ time average = bcos (β−θ−φ)
(5)
It becomes.
Thereby, the phase of the reference signal can be arbitrarily changed. Actually, the phase is not changed, but the value of “measurement signal × time average of reference signal” when changed is calculated and output by the digital signal processing device (DSP) 31.

sin成分について書くと以下のとおりである。
元々の参照信号の位相では、前述のように
S・Rcの時間平均=bcos(β−θ)
S・Rsの時間平均=bsin(β−θ)
であり、参照信号の位相をφ増すと、
−S・Rc・sinφ+S・Rs・cosφの時間平均=bsin(β−θ−φ)
(6)
となる。
これにより、参照信号の位相は任意に変えることができる。図5参照。実際には、位相は変えていないが、変えた場合の“測定信号×参照信号の時間平均”の値がデジタルシグナル処理装置(DSP)31で算出され、出力される。
The sin component is written as follows.
In the phase of the original reference signal, the time average of S · Rc = b cos (β−θ) as described above.
Time average of S · Rs = bsin (β−θ)
When the phase of the reference signal is increased by φ,
−S · Rc · sinφ + time average of S · Rs · cosφ = bsin (β−θ−φ)
(6)
It becomes.
Thereby, the phase of the reference signal can be arbitrarily changed. See FIG. Actually, the phase is not changed, but the value of “measurement signal × time average of reference signal” when changed is calculated and output by the digital signal processing device (DSP) 31.

以上、図4及び図5の場合における参照信号の位相の変更方法について説明してきた。実際には位相は変えていないが、変えたときと同じ結果を計算で求めている。   The method for changing the phase of the reference signal in the case of FIGS. 4 and 5 has been described above. Actually, the phase is not changed, but the same result as when it is changed is obtained by calculation.

以上のようにして、差動トランス37のコアの変位は、デジタルシグナル処理装置(DSP)31を用いたデジタルロックインアンプで測定できる。参照信号の位相を調整しておけば、測定したい信号と参照信号を掛け算して低域通過フィルタ(LPF)に通せば、差動トランス37のコアの変位に比例する値が算出される。この低域通過フィルタ(LPF)もデジタルシグナル処理装置(DSP)31で、デジタルフィルタで計算処理される。なお、アナログ−デジタル変換器の前にはアンチエイリアシングフィルタが設けられており、測定したい信号を、それと同じ周波数の参照信号と掛け算して低域通過フィルタ(LPF)に通すことで、その周波数成分だけを取り出し、その信号の振幅、位相の情報を得るようにしている。   As described above, the displacement of the core of the differential transformer 37 can be measured by the digital lock-in amplifier using the digital signal processing device (DSP) 31. If the phase of the reference signal is adjusted, a value proportional to the displacement of the core of the differential transformer 37 is calculated by multiplying the signal to be measured by the reference signal and passing through the low-pass filter (LPF). This low-pass filter (LPF) is also calculated by a digital signal processing device (DSP) 31 using a digital filter. In addition, an anti-aliasing filter is provided in front of the analog-digital converter, and a frequency component is obtained by multiplying a signal to be measured by a reference signal having the same frequency and passing it through a low-pass filter (LPF). Only the amplitude and phase of the signal are obtained.

このようにしてデジタルシグナル処理装置(DSP)31において、前述の例では差動トランス37のコアの変位zが5μsごとに求まる。これを同一のデジタルシグナル処理装置(DSP)31でモニターし、監視し、それを元に針圧付加手段38への電流を制御すればよい。その制御のアルゴリズムは特許文献1に記載のものと同じである。   In this way, in the digital signal processing device (DSP) 31, in the above example, the core displacement z of the differential transformer 37 is obtained every 5 μs. This may be monitored by the same digital signal processing device (DSP) 31 and monitored, and the current to the needle pressure applying means 38 may be controlled based on this. The control algorithm is the same as that described in Patent Document 1.

参照信号Rcと参照信号Rsは互いに位相が90度ずれている。参照信号を外部から取る場合に、その参照信号の位相をずらす方法は既に示したとおりであり、参照信号Rcと参照信号Rsの両方が必要である(式(5)、(6)参照)。そのためには前述のように例えば図8に示すように40点で1周期を表わすと、現在の、参照に用いる外部信号電圧値をRcとして、それより30点前の電圧値をRsとして、式(5)、(6)で用いればよい。   The reference signal Rc and the reference signal Rs are 90 degrees out of phase with each other. When taking the reference signal from the outside, the method of shifting the phase of the reference signal is as already described, and both the reference signal Rc and the reference signal Rs are necessary (see equations (5) and (6)). For this purpose, as described above, for example, when one cycle is represented by 40 points as shown in FIG. 8, the current external signal voltage value used for reference is Rc, and the voltage value 30 points before that is Rs. (5) and (6) may be used.

外部発振器40から取り込んだ参照信号の位相の変更は、前述のようにして行われる。式(5)における「時間平均」は低域通過フィルタ、カットオフ周波数20Hzのデジタルフィルタに通した。デジタルフィルタはIIR、縦続型、バタワース4次で、カットオフ周波数1000Hzでも測定した。デジタルシグナル処理装置(DSP)31で得られた演算結果は変換回路32におけるデジタル−アナログ変換器32dでアナログ信号にして、設定、表示用コンピュータ39へ送り表示される。   The phase of the reference signal taken from the external oscillator 40 is changed as described above. The “time average” in equation (5) was passed through a low-pass filter and a digital filter with a cutoff frequency of 20 Hz. The digital filter was IIR, cascade type, Butterworth 4th order, and the measurement was performed at a cutoff frequency of 1000 Hz. The calculation result obtained by the digital signal processing device (DSP) 31 is converted into an analog signal by the digital-analog converter 32d in the conversion circuit 32 and sent to the setting / display computer 39 for display.

前記の説明において、過去の30点前の電圧値Rsは、デジタルシグナル処理装置(DSP)31におけるメモリに記憶しておけばよいが、リングバッファを用いれば、一度に書き換える量が少なくて済むので、時間の無駄やデジタルシグナル処理装置(DSP)31の処理の負担も軽減する。   In the above description, the voltage value Rs 30 points before the past may be stored in the memory in the digital signal processing device (DSP) 31, but if a ring buffer is used, the amount of rewriting at a time can be reduced. In addition, waste of time and processing load of the digital signal processing device (DSP) 31 are reduced.

以上説明してきたように、デジタルシグナル処理装置(DSP)で探針の変位計測と針圧付加手段の力の制御の両方が可能となり、計測装置と制御装置をそれぞれ設ける必要がなく、探針のとびを小さくすることができる小型、安価な計測制御回路で針のとびを小さく抑制できる。   As described above, the digital signal processing device (DSP) can both measure the displacement of the probe and control the force of the needle pressure applying means, and there is no need to provide a measuring device and a control device. With a small and inexpensive measurement control circuit that can reduce the jump, the needle jump can be reduced.

図9には、センサヘッド36における差動トランス37のコアの変位の測定結果を示す。デジタルシグナル処理装置(DSP)31でのLPFカットオフ20Hzに通したデータを、設定、表示用コンピュータ39でさらにLPFカットオフ13Hzで処理した結果である。図7のグラフからピーク−ピークが1nm程度と十分に小さい雑音で計測ができていることがわかる。   FIG. 9 shows the measurement result of the displacement of the core of the differential transformer 37 in the sensor head 36. This is the result of processing the data passed through the LPF cutoff of 20 Hz in the digital signal processing device (DSP) 31 with the LPF cutoff of 13 Hz in the setting and display computer 39. It can be seen from the graph of FIG. 7 that measurement can be performed with sufficiently small noise, with a peak-peak of about 1 nm.

図10には入力換算電圧雑音密度の周波数依存性を示す。デジタルシグナル処理装置(DSP)31でのLPFカットオフ20Hzでの結果である。この計算では測定信号の振幅を求めているが、RMSで表示する方法もあり、その表示法では10Hz以下の領域で4nV/Hz^0.5となり雑音は十分に小さい。   FIG. 10 shows the frequency dependence of the input converted voltage noise density. It is a result in LPF cutoff 20Hz in the digital signal processor (DSP) 31. In this calculation, the amplitude of the measurement signal is obtained, but there is also a method of displaying by RMS. In this display method, the noise is sufficiently small at 4 nV / Hz ^ 0.5 in a region of 10 Hz or less.

ロックイン増幅器では、測定信号の振幅A、参照信号との位相差φとして、A cosφが計測され出力される。例えば、エヌエフ回路設計ブロック社の市販のデジタルロックイン増幅器LI5640では、測定信号の実効値Armsが出力され、表示される。この場合、上記との対応では、Arms cosφが出力される。実験では、振幅を測定しA cosφを出力している。Arms =0.707×A なので、エヌエフ回路設計ブロック社の表し方では、0.707倍になる。
図10はA cosφの電圧雑音密度を示しており、Arms cosφの電圧雑音密度も同様に0.707倍になっている。
In the lock-in amplifier, A cos φ is measured and output as the amplitude A of the measurement signal and the phase difference φ from the reference signal. For example, in the commercially available digital lock-in amplifier LI5640 manufactured by NF Circuit Design Block, the effective value Arms of the measurement signal is output and displayed. In this case, Arms cos φ is output in correspondence with the above. In the experiment, the amplitude is measured and A cosφ is output. Since Arms = 0.707 x A, it is 0.707 times in the way of NF circuit design block company.
FIG. 10 shows the voltage noise density of A cos φ, and the voltage noise density of Arms cos φ is also 0.707 times.

図10では、10Hz以下では約6 nV/Hz^0.5である。6 Hzの雑音は環境(床の振動)によるもの、2 Hzの雑音は用いた空気式除振台の固有振動数に起因するものと思われ、計測器自体の実力は約6 nV/Hz^0.5と思われる。なお、2や6 Hzの雑音は、昼休みや夜になり周りの活動が減ると、小さくなる。環境による、センサコアとコイル間の相対位置の振動によるもので、計測器自体の性能の問題ではない。   In FIG. 10, it is about 6 nV / Hz ^ 0.5 below 10 Hz. The 6 Hz noise is due to the environment (floor vibration), the 2 Hz noise is probably due to the natural frequency of the pneumatic vibration isolation table used, and the measuring instrument itself is about 6 nV / Hz ^ It seems 0.5. In addition, 2 and 6 Hz noise will be reduced during lunch breaks and nights and when the surrounding activities are reduced. This is due to the vibration of the relative position between the sensor core and the coil due to the environment, and is not a problem of the performance of the measuring instrument itself.

図10は、デジタルシグナル処理装置(DSP)31でカットオフ20Hzの低域通過フィルタ、バタワース、デジタルフィルタをかけた結果を示している。バタワースならカットオフ周波数で0.707倍になるはずで、図では20Hzで3.5 nV/Hz^0.5になっており、逆算すると低域での白色雑音(フラットな雑音)は3.5/0.707で約5 nV/Hz^0.5となり、上記の6 nV/Hz^0.5程度またはそれを上回るくらいの性能が確かに出ていると思われる。   FIG. 10 shows the result of applying a low-pass filter, Butterworth, and digital filter with a cutoff of 20 Hz in the digital signal processing device (DSP) 31. In the case of Butterworth, the cutoff frequency should be 0.707 times, and in the figure it is 3.5 nV / Hz ^ 0.5 at 20 Hz. Hz ^ 0.5, and it seems that the performance of about 6 nV / Hz ^ 0.5 or above is certainly out.

この実施形態においても、デジタルシグナル処理装置(DSP)31から針圧付加手段の力発生コイル38への電流経路を設けて、その電流を特許文献1に記載のアルゴリズムを用いてデジタルシグナル処理装置(DSP)31で制御すれば、小型で安価な計測制御回路で探針のとびを小さくできる。   Also in this embodiment, a current path is provided from the digital signal processing device (DSP) 31 to the force generation coil 38 of the needle pressure applying means, and the current is converted into a digital signal processing device (by using the algorithm described in Patent Document 1). If the control is performed by the DSP 31, the probe skip can be reduced with a small and inexpensive measurement control circuit.

1:固定支持台
2:支点
3:揺動支持棒
4:探針
5:針圧付加手段
6:検出手段
7:試料ホルダー
8:走査ステージ
9:被測定試料
30:計測制御回路装置
31:デジタルシグナル処理装置(DSP)
31a:Sin波発生回路
31b:振幅調整回路
31c:振幅・位相調整回路
31d:掛算回路
31e:低域通過フィルタ
32:変換回路
32a:アナログ−デジタル変換器
32b:デジタル−アナログ変換器
32c:デジタル−アナログ変換器
32d:デジタル−アナログ変換器
32e:アナログ−デジタル変換器
33:低域通過フィルタ(LPF)
34:前置増幅器
35:電圧−電流変換回路
36:触針式段差計のセンサヘッド
37:差動トランス
38:針圧付加手段の力発生用コイル
39:設定、表示用のコンピュータ
40:外部発振器
41:低域通過フィルタ(LPF)
1: Fixed support base 2: Supporting point 3: Swing support rod 4: Probe 5: Needle pressure application means 6: Detection means 7: Sample holder 8: Scan stage 9: Sample to be measured 30: Measurement control circuit device 31: Digital Signal processor (DSP)
31a: Sin wave generation circuit 31b: Amplitude adjustment circuit 31c: Amplitude / phase adjustment circuit 31d: Multiplication circuit 31e: Low-pass filter 32: Conversion circuit 32a: Analog-digital converter 32b: Digital-analog converter 32c: Digital- Analog converter 32d: Digital-analog converter 32e: Analog-digital converter 33: Low-pass filter (LPF)
34: Preamplifier 35: Voltage-current conversion circuit 36: Sensor head of stylus type step meter 37: Differential transformer 38: Coil for force generation of needle pressure applying means 39: Computer for setting and display 40: External oscillator 41: Low-pass filter (LPF)

Claims (9)

被測定試料の表面に対して垂直方向に移動可能でしかも被測定試料の表面に沿って相対的に移動可能である探針と、
探針に被測定試料の表面に対して垂直方向に向う針圧を作用させる針圧付加手段と、
探針の垂直方向の変位を検出する差動トランスと、
差動トランスの出力信号に基き探針のとびを検出すると共に探針のとびの検出に応じて針圧付加手段を制御して探針の針圧を増減する制御手段と
を有する触針式段差計による試料の表面形状の測定用の計測制御回路装置において、
差動トランスの一次側に印加される一次電圧と同じ周波数の信号を位相調整して参照信号を形成し、この参照信号と探針の垂直方向の変位を検出する差動トランスの二次側からの検出した信号とを掛算処理し、探針の垂直方向の変位値を表す信号を発生するデジタル信号処理装置と、
針圧付加手段の力発生用コイルの電流値を制御する制御信号を発生する回路と
を有することを特徴とする計測制御回路装置。
A probe that is movable in a direction perpendicular to the surface of the sample to be measured and is relatively movable along the surface of the sample to be measured;
Needle pressure application means for applying a needle pressure in the direction perpendicular to the surface of the sample to be measured to the probe;
A differential transformer for detecting the vertical displacement of the probe;
A stylus type step having a control means for detecting a probe jump based on an output signal of the differential transformer and controlling a needle pressure applying means in accordance with the detection of the probe jump to increase or decrease the needle pressure of the probe. In the measurement control circuit device for measuring the surface shape of the sample with a meter,
A reference signal is formed by phase-adjusting a signal having the same frequency as the primary voltage applied to the primary side of the differential transformer, and from the secondary side of the differential transformer that detects the vertical displacement of the reference signal and the probe. A digital signal processing device that multiplies the detected signal and generates a signal that represents the vertical displacement value of the probe;
And a circuit for generating a control signal for controlling the current value of the force generating coil of the needle pressure applying means.
デジタル信号処理装置が、sin波を発生するsin波発生回路と、sin波発生回路で発生したsin波を振幅調整する振幅調整回路とを備え、差動トランスの一次側に印加される一次電圧を出力するように構成されていることを特徴とする請求項1記載の計測制御回路装置。   The digital signal processing apparatus includes a sine wave generation circuit that generates a sine wave and an amplitude adjustment circuit that adjusts the amplitude of the sine wave generated by the sine wave generation circuit, and a primary voltage applied to the primary side of the differential transformer. The measurement control circuit device according to claim 1, wherein the measurement control circuit device is configured to output. デジタル信号処理装置が、さらに、sin波発生回路で発生したsin波を振幅及び位相調整して参照信号を発生する振幅・位相調整回路を備えていることを特徴とする請求項1記載の計測制御回路装置。   2. The measurement control according to claim 1, wherein the digital signal processing apparatus further includes an amplitude / phase adjustment circuit that generates a reference signal by adjusting an amplitude and a phase of a sine wave generated by the sine wave generation circuit. Circuit device. 参照信号が、差動トランスの一次側に印加される一次電圧と同じ周波数で位相を調整された信号であることを特徴とする請求項1記載の計測制御回路装置。   The measurement control circuit device according to claim 1, wherein the reference signal is a signal whose phase is adjusted at the same frequency as the primary voltage applied to the primary side of the differential transformer. 参照信号を発生する振幅・位相調整回路が、外部発信器より差動トランスの一次側に印加される一次電圧から分岐した電圧を受け、振幅及び位相調整して参照信号を発生するように構成されていることを特徴とする請求項1記載の計測制御回路装置。   An amplitude / phase adjustment circuit that generates a reference signal is configured to receive a voltage branched from a primary voltage applied to the primary side of a differential transformer from an external transmitter and generate a reference signal by adjusting the amplitude and phase. The measurement control circuit device according to claim 1, wherein: 1周期の1/4ずれた時点での参照信号の値を用いて測定信号のcos成分とsin成分とを同時に得るように構成されたデジタルロックイン増幅器を備えていることを特徴とする請求項5記載の計測制御回路装置。   5. A digital lock-in amplifier configured to obtain a cos component and a sin component of a measurement signal at the same time using a value of a reference signal at a time shifted by 1/4 of one cycle. 5. The measurement control circuit device according to 5. デジタル信号処理装置が、参照信号と差動トランスの二次側に発生した測定信号とを掛算する掛算回路と、掛算回路からの信号をフィルタリング処理して、雑音を含む測定信号の中から参照信号と同じ周波数成分を取り出す低域通過フィルタ回路とを備え、算出した測定信号の振幅及び位相に基き、差動トランスのコアの変位を求めるように構成されたデジタルロックイン増幅器から成ることを特徴とする請求項1記載の計測制御回路装置。   The digital signal processor multiplies the reference signal and the measurement signal generated on the secondary side of the differential transformer, and the signal from the multiplication circuit is filtered to perform reference processing from the measurement signal including noise. And a low-pass filter circuit for extracting the same frequency component as the digital signal, and comprising a digital lock-in amplifier configured to obtain the displacement of the core of the differential transformer based on the calculated amplitude and phase of the measurement signal. The measurement control circuit device according to claim 1. デジタル信号処理装置が、差動トランスの一次側に印加されるsin波の一次電圧の周波数が5kHzであり、差動トランスの二次コイルに発生する二次電圧を200kS/sでAD変換して読み込み、5μs毎に計算処理するように構成されていることを特徴とする請求項1記載の計測制御回路装置。   The digital signal processing device AD-converts the secondary voltage generated in the secondary coil of the differential transformer at 200 kS / s when the frequency of the primary voltage of the sine wave applied to the primary side of the differential transformer is 5 kHz. The measurement control circuit device according to claim 1, wherein the measurement control circuit device is configured to read and perform calculation processing every 5 μs. デジタル信号処理装置が、算出した測定信号の振幅及び位相に基き、針圧付加手段の力発生用コイルの電流値を制御するように構成されることを特徴とする請求項1記載の計測制御回路装置。   2. The measurement control circuit according to claim 1, wherein the digital signal processing device is configured to control the current value of the force generating coil of the needle pressure applying means based on the calculated amplitude and phase of the measurement signal. apparatus.
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Publication number Priority date Publication date Assignee Title
US20100288033A1 (en) * 2007-07-13 2010-11-18 Naoki Mizutani Method and apparatus for measuring surface profile of sample
JP2016139854A (en) * 2015-01-26 2016-08-04 株式会社ソシオネクスト Electronic circuit, power supply circuit, measurement method for circuit characteristics, and calculation program for amplitude and phase characteristics

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006317419A (en) * 2005-05-16 2006-11-24 Boc Edwards Kk Position sensor, and magnetic bearing device mounted with the sensor
JP2009020050A (en) * 2007-07-13 2009-01-29 Ulvac Japan Ltd Method and apparatus for measuring surface shape of specimen
JP2009133730A (en) * 2007-11-30 2009-06-18 Ulvac Japan Ltd Step measuring method and device using stylus type step profiler for surface shape measurement

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006317419A (en) * 2005-05-16 2006-11-24 Boc Edwards Kk Position sensor, and magnetic bearing device mounted with the sensor
JP2009020050A (en) * 2007-07-13 2009-01-29 Ulvac Japan Ltd Method and apparatus for measuring surface shape of specimen
JP2009133730A (en) * 2007-11-30 2009-06-18 Ulvac Japan Ltd Step measuring method and device using stylus type step profiler for surface shape measurement

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20100288033A1 (en) * 2007-07-13 2010-11-18 Naoki Mizutani Method and apparatus for measuring surface profile of sample
US8474147B2 (en) * 2007-07-13 2013-07-02 Ulvac, Inc. Method and apparatus for measuring surface profile of sample
JP2016139854A (en) * 2015-01-26 2016-08-04 株式会社ソシオネクスト Electronic circuit, power supply circuit, measurement method for circuit characteristics, and calculation program for amplitude and phase characteristics

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