3ft&lWS〇4號申請案86年1月30Θ修正本A7 B7Application for 3ft & lWS〇4 January 86, 30Θ Amendment A7 B7
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I 經濟部中央標準局員工消費合作社印製 五、發明説明（01) 發明背景 本發明係有關於電漿產生設 測射頻電源之電流和電壓的探針 射頻電漿室。 在一般的射頻電漿產生裝置 源會產生具有一預定頻率的射頻 ，並且將這電波沿著一個電力管 一般在該射頻電源和電漿室之間 ，一個阻抗匹配網路被設置在兩 有非線性存在，因為這個緣故、 路中的損失，射頻產生器的輸出 此，傳統上在電漿室的電源入口 該射頻電波進入電漿室時的電壓 電漿室的位置處精確地測量電壓 使用者可以獲得較佳的電漿品質 的蝕刻特性產生較佳的控制。 在目前，二極體探針被用來 度。這些探針僅使用二極體來修 遞一個電壓和電流的簡單直流計 。這些探針在此一用途上至少有 在低度的訊號電平時，其本質上 知是易於遭受到溫度偏移的變化 基本頻率的訊號頂峰値，並且對 的較高頻率，無法產生任何訊息 - 4 - 備，並且特別針對用於偵 ’該射頻電源係被供輸給 之中， 電波， 道傳送 會有嚴 者之間 以及在 不會全 處使用 和電流 和電流 指標》 高功率'的射 譬如是1 3. 到一電漿室 重的阻抗失 。由於在電 電線與阻抗 部到達電漿 一個探針， 。藉由儘可 ’使得電漿 這將必然對 頻產生 56 MHz 。因為 配情形 漿室裏 匹配網 室。因 以傾知 能靠近 加工的 珍晶片 請 先 閱 讀 背 面 之 注 意 事 項 再 填 馬 本 頁 偵測電流和電壓波形的幅 正電壓和電流波形，並傳 量輸出（metering output) 兩個缺點。二極體偵測器 係非線性的’並且眾所皆 。二極體也受限於只偵測 於出現在射頻電源波形裏 °這意謂著對於任何错波 本紙張尺度適用中國國家標準（CNS ) A4規格（210X297公釐） A7 308778 五、發明説明（02) 資料，無法取得「措波指印（harmonic fingerprint)」 ，同時，當該波形富含諧波的時候，電源的測量也是不 精確的。而在電漿作業之中，這種諧波情形是常見的事。 除了這個以外，它也無法取得電流波形和電壓波形之間相 位角的資料，這也使得電源測量較不準確。 已經被考慮用來改良射頻電源偵測的一種建議是要取 得探針的電壓輸出和電流輸出之數位樣本。該方法是使用 閃光轉換（f lash conversion)，然後在高速的隨機存取記 憶體（RAM)緩衝器上，處理這些樣本。目前，閃光轉換有 一個低的動態範園（dynamic range)，該範圍被限制在大 約八個位元。為了要獲得合理的相位精確性，以符合電衆 客户的需求’必須要達到大約十二位元的精度，以便在全 功率之下’獲得比一度更佳的相位角精確度。另外，閃光 轉換需要一個極快的隨機存取記憶體，以便能夠在數位訊 號處理器（DSP)對某一區塊的樣本進行處理之前，暫時緩 衝調度這個樣本區塊，並且隨機存取記憶體線路是既佔空 間，且是昂贵的。 發明之概論輿目的 本發明之目的是要提供一個可靠但低成本的探針，用 於偵測供輸給電漿室的射頻電源之電流和電壓並且該探 針能夠避免傳統技術的缺點。 本發明更明確之目的是要提供—種交接點取樣策略， 以供偵測射頻電流和電壓的波形，並且該策略能夠保存諧 波和相位資料。 -5 - 本紙張尺度適用中國國家標率（CNS ) A4規格（21GX 297公釐）~ ~~------------ T-------——『裝------訂-------^ (請先閱讀背面之注意事項再填寫本頁) 經濟部中央標準局負工消費合作社印裝 308778 A7 B7 經濟部中央標準局負工消費合作社印製 五、發明説明（〇3) 本發明之另一目的是要提供一種 策略能夠提供電壓、電流、和相位的 受溫度偏移的影響。 本發明更明確之目的是要提供一 該裝置能夠對於所施加的射頻電流波 產生遠較為低的頻率之複製波形，保 相位和諧波資料。 根據本發明之一特徵，交接點取 漿裝置，在該裝置裏，射頻電源產生 率的射頻電波，謦如是13. 56 MHz， 配網路，被施加到電漿室的電源輸入 射頻電波產生電漿，該電漿可用來在 上作蝕刻、塗裝或沉積作業》該電漿 預測和可重複，以確保產品品質的一 個目的，電漿加工的使用者需要持續 且根據所偵測得到的電源量測結果， 加工。由於電漿加工過程裏的非線性 假如能夠取得這些諧波的資料，可以 價値資料。同時，因為在電壓波形和 現明顯的相位差異，施加的功率極少 流的簡單乘積。 為了達到這個目的，一個交接點 的取樣速率fs，對該射頻電壓的振 進行採樣，該取樣速率明顯低於所施 交接點取樣策略，該 高精確性，並且較不 種交接點取樣裝置， 形和射頻電壓波形， 存實際施加的波形之 樣探針 器會產 該電波 口。在 譬如是 加工應 致性。 地監控 作調整 ，許多 帶來有 電流波 是峰値 被用來 生一個 經由一 電漿室 梦晶片 該儘可 為了要 電源特 或停止 諧波會 關該電 形之間 電壓和 連接電 預定頻 阻抗匹 内部， 的基片 能地可 達到這 性，並 該電漿 出現， 漿的有 能夠出 峰値電 取樣電路以預先設ί 幅和射頻電流的振中 加射頻電源之預定4 (請先閲讀背面之注意事項再填寫本頁) - 6 - 經濟部中央標準局貞工消費合作社印製 A7 B7 五、發明説明（04) 頻基本頻率F，謦如是13·56ΜΗζ。這會產生射頻波形的 複製波形，但是該複製的波形具有一較低的疊合頻率fa (aliasing frequenCy)，誓如是i〇〇 KHz。產生出來的疊 合波形保留有原始波形的諧波資料，並且在個別的疊合波 形襄’留存著電壓和電流波形之間的相對相位、。由於電漿 特性的偏移和改變較為緩慢，在射頻電波數千個周期範圍 以内沒有明顯變化，因此能夠產生精確的疊合波形。 取樣頻率能夠按照下列的公式選擇 fs = F/N +/~ fa/N5 其中，N是一個大於1的整數。更明確地説，若是 感興趣的最高諧波是第n次諧波，誓如是：所施加的射 頻電源第五次諧波，那麼，整數Ν應被選擇為等於或大 於該諧波數η。如前所述，電源的基本頻率正常是13.56 MHz。典型的疊合頻率能夠是在大約5〇 KHz和250 KHz 之間。 在一實際的實施例裏，取樣電路包含一個以取樣速率 fs操作的取樣時鐘、和由取樣時鐘操作的第一與第二採 樣與保持線路，以便於對該射頻電波的電流和電壓進行取 樣。這些樣本被數位化成為十二位元字，並且被結合到一 個數位訊號處理器或稱DSP的數位輸入襄。電壓和電流 波形被同時取樣’這使得DSP能夠產生電壓和電流波形 在同一時刻的重疊代表訊號。在一個實際的例子裏，交接 點取樣器產生疊合頻率為100 KHz的複製波形，其精確 度足以分辨第五諧波，並且能夠使相位保持在大約一度範 本紙張尺度適用中國國家標準（CNS ) A4規格（21〇Χ297公釐） (請先閲讀背面之注意事項再填寫本頁) 裝. 訂 經濟部中央標準局員工消費合作杜 308778 五、發明説明（05) 圍以内。一旦，數位樣本被儲存在該Dsp内部一種算 法規則，誓如是快速的傅立葉轉換（FFT)，可以用來對這 些樣本進行運算，以產生一组頻域（frequency d〇fflain) 樣本，該頻域樣本也可以被用來控制電漿操作，或被用來 作進一步的分析。 圖式之簡單説明 圖1係射頻電漿裝置的方塊囷，該射頻電漿裝置包含 有根據本發明較佳實施例的射頻電源產生器、阻抗匹配網 路、電漿室、和射頻電源探針。 圖2係本發明之探針實施例的交接點取樣部份的簡化 示意圖。 圖3 A至囷3 C係解釋本發明實施例裏施加的射頻電 源波形、取樣脈衝、和所取得樣本的振幅數値。 囷4係本實施例產生的重|波形。 較佳實施例之詳細説昍 圖1係一個電漿加工裝置丨0，譬如是用來蝕刻一矽晶 片或其它工件，該電漿加工裝置具有一個射頻電源產生器 ’能夠產生一規定頻率的射頻電力，例如是13.56MH;z，所 產生的電力係為一預定的電功率大小，譬如是一千瓦，並 且沿著一管道14’將射頻電源供輸給一匹配網路16。匹配 網路16的輸出是由一電力管道18聯結到一個電漿室20的輸 入口。一個探針裝置22係設置在電漿室20入口處的管道18 上面，而該探針裝置係用來採樣所施加的射頻電源之電壓 V-和電流Irf。採得的電壓Vrf和電流1以沿著線路24和26 — 8 - 4用中國國家標準（CNS ) A4規格（210X 297公釐） I ^n> *^^1 ί —l·— 1^1 HI In 1^1 \〆m —ί HI m * C请先知讀背希之注翥事項#填寫本頁'> A7 A7 經濟部中央標準局员工消費合作社印製 til 五、發明説明（06) 被送往一個交接點取樣器28的輸入口，該取樣器以較射頻 電源波形每N周一次的速度稍慢或稍快的取樣速率，採取 電壓和電流的振幅樣本。這會產生一組數位値，這組數値 被輸送到一數位訊號處理器或稱DSP30。該DSP處理這些樣 本數値，並且提供一個電流和電壓的分析給予、輸出裝置32 ’該輸出裝置能夠經由一個回積線路34，連接控制射頻電 源產生器1 2 » 交接點取樣器28的細節係顯示在圖2的示意圖中。在 該圖襄，一個取樣時鐘36提供取樣脈衝給予—個電壓取樣 與保持電路38和一個電流取樣與保持電路42、並對Dsp 3〇 提供中斷輸入訊號。沿著線路24傳輸的電壓樣本vrf和沿 著線路26傳輸的電流樣本irf具有基本頻率1356 mHz，但 不是正弦波形，並且可能如圖3A的波形一樣，含有較多 的諧波。取樣脈衝S(圖3 B)發生的時間間隔稍大於一些 預定的射頻電源波形的整數周波數目。例如，取樣脈衝可 能具有一個等於十又十分之一個完整循環的時間間隔，或 是九又十分之九個完整循環周數的時間間隔。在任一種情 形裏，高速取樣與保持線路維持著振幅水平，如囷3^所 示，並且這些連續的取樣水平孝皮合成以產生一㈣合波形 ’如圖4所示。這些*合波形具有如圖3a所示的脈波形 狀’但係在一遠較為低的頻率，譬如县 功干管如是原有頻率13. 56MHz 的百分之一。 現在以圈2繼續説明本發明的内容，取樣與保持線路 38包含有-個類比-數位轉換器，或稱為a — d轉換器， -Γ---—.---，、裝------訂-----Λ.ξ (請先聞讀背面之注意事項再填寫本頁) A7 308778 B7 五、發明説明（0 7) (請先閱讀背面之注意事項再填寫本頁) 該轉換器將取樣所得的數値（囷3 C)轉換為數位的形式， 並帶有至少十二位元的解析度。這些樣本經由一個十二位 元的匯流排送至一閂鎖電路40，該電路將這個十二位元樣 本連接到DSP30的資料輸入口。取樣時鐘脈衝36也被供輸 至第二高速取樣與保持電路42，該電路也同樣'包含有一個 類比一數位轉換器。電路42對於從探針22沿著線路26輸入 的射頻電流樣本的振幅進行取樣。該電路提供一連串的十 二位元樣本給予閂鎖電路44，而該閂鎖電路提供樣本作為 DSP30的電流資料輸入》 在一個實際的例子裏，取樣時鐘36是以2. 732MHz取樣 頻率fs操作《而如此會以ΙΟΟΚΗζ的基本頻率產生吞合波形 (aliasing waveform)。 射頻樣本進入兩個取樣與保持電 路38、42’該取樣與保持電路同時取樣電壓Vrf和電流Irf 的波形，以產生ΙΟΟΚΗζ的疊合波形（圖4)。要達到此目的 ’該13. 56MHz的波形是以1 3, 60 0KHz加上（或減去）l〇〇KHz 的整數分之一（1/Ν)，也就是·· 經濟部中央標準局貝工消費合作社印製 fs = 13,560,000/N +/- 100,000/N 假如操作者的目標是要獲得有關第五諧波的可靠資料 ，那麼疊合波形必須要有50OKHz的頻率。為了達到這個目 的’我們選擇 N = 5 並且獲得一個取樣頻率 fs = 13,560,000/5 +/- 100,000/5 實際的取樣頻率應該視所需要的解析度來決定。在這 一 10 - 本紙張尺度逋用中國國家標準（CNS ) A4規格（210X297公釐） A7 B7 五、發明説明（08) 個案例襄，諧振頻率500KHz充分適合本例子2.732/2 MHz 的取樣之理論限制《如圖3 B所示，取樣訊號S具有周期 Ts = 1/f s，大約是366nsec，以及脈衝寬度大小約為1至5 nsec。該射頻電波具有周期τ為1/1 3. 56MHz或73. 75nsec (圖 3 A )。 在本實施例之中，該DSP 30—般能夠使用高速中斷通 路’以2.732MHz的取樣速率，接收一區塊的樣本，以便進 行快速傅立葉轉換（FFT)或其它的處理作業。當樣本已經 被儲存在DSP 30的記憶艘内的時候，一個運算法則，譬如 是一個FFT’可以被用來運算該樣本區塊，以便於產生一 組頻域樣本的集合。該被處理過的資料然後被送往一個電 腦主機（圖中未表示出來），以便進行更進一步的分析，或 是用作為控制上的用途，以便從電漿加工上獲得最大的產 品品質。 HI I! -I In (n.— —l·— ml m^ ^^1 ^^1 ^^1 11 1^1 •--¾ (請先閲讀背面之注意事項再填寫本頁) 經濟部中央標準局貝工消费合作社印褽^ " ΙτΠ .. ·· β. · * Printed from _. I Central Ministry of Economic Affairs Employee Consumer Cooperative V. Description of the invention (01) Background of the invention The present invention relates to plasma generation and measurement of RF power supply current and Voltage probe RF plasma chamber. In a general radio frequency plasma generating device, the source will generate radio frequency with a predetermined frequency, and the radio wave will be along a power tube generally between the radio frequency power source and the plasma chamber, and an impedance matching network is provided between the two Linearity exists, because of this, the loss in the circuit, the output of the RF generator, traditionally, the voltage is accurately measured at the position of the plasma chamber at the position of the plasma chamber at the power inlet of the plasma chamber when the radio frequency waves enter the plasma chamber Etching characteristics for better plasma quality can be obtained to produce better control. At present, diode probes are used for degrees. These probes use only diodes to modify a simple DC meter for voltage and current. These probes have at least a low signal level in this application, which is essentially known as the signal peak value of the basic frequency that is susceptible to changes in temperature drift, and for higher frequencies, it cannot generate any information- 4-Prepared, and especially aimed at detecting the radio frequency power system is supplied to the transmission, the radio wave, the channel transmission will be between the strict and will not be used everywhere and the current and current index "high power" radiation For example, 1 3. The impedance loss to a plasma chamber is heavy. Because a probe reaches the plasma in the electric wire and impedance part. By making as much as possible, the plasma will inevitably produce 56 MHz in frequency. Because of the matching situation, the pulp room matches the net room. Because you know the precious wafers that can be processed close to you, please read the notes on the back and then fill in this page. Detect the amplitude of the current and voltage waveforms. Positive voltage and current waveforms, and the two disadvantages of metering output. Diode detectors are non-linear and are everywhere. The diode is also limited to being detected only in the RF power waveform. This means that the Chinese National Standard (CNS) A4 specification (210X297mm) is applicable to any wrong wave paper size. A7 308778 V. Description of invention ( 02) Data, "harmonic fingerprint" cannot be obtained. At the same time, when the waveform is rich in harmonics, the measurement of the power supply is also inaccurate. In plasma operation, this harmonic situation is common. In addition to this, it can not obtain the phase angle data between the current waveform and the voltage waveform, which also makes the power measurement less accurate. One suggestion that has been considered to improve RF power detection is to obtain digital samples of the voltage output and current output of the probe. The method is to use flash conversion, and then process these samples on a high-speed random access memory (RAM) buffer. Currently, flash conversion has a low dynamic range, which is limited to about eight bits. In order to obtain reasonable phase accuracy, in order to meet the needs of electric customers, it is necessary to achieve an accuracy of approximately twelve bits in order to obtain a phase angle accuracy better than one degree at full power. In addition, flash conversion requires a very fast random access memory, so that before a digital signal processor (DSP) processes a block of samples, the sample block is temporarily buffered and scheduled, and the random access memory Lines take up space and are expensive. SUMMARY OF THE INVENTION The object of the present invention is to provide a reliable but low-cost probe for detecting the current and voltage of the RF power supply to the plasma chamber and the probe can avoid the disadvantages of the conventional technology. The more specific purpose of the present invention is to provide a junction sampling strategy for detecting the waveforms of radio frequency current and voltage, and the strategy can save harmonic and phase data. -5-This paper scale is applicable to China National Standard (CNS) A4 specification (21GX 297mm) ~ ~~ ------------ T ----------- "installed- ----- Subscribe ------- ^ (Please read the notes on the back before filling out this page) Printed and printed by the Ministry of Economic Affairs Central Standardization Bureau Negative Work Consumer Cooperative 308778 A7 B7 Ministry of Economic Affairs Central Standardization Bureau Negative Work Consumer Cooperative Print 5. Description of the invention (〇3) Another object of the present invention is to provide a strategy that can provide voltage, current, and phase that are affected by temperature drift. A more specific object of the present invention is to provide a device capable of generating a replica waveform of a much lower frequency for the applied RF current wave, maintaining phase and harmonic data. According to one feature of the present invention, a plasma pick-up device at a junction, in which a radio frequency radio wave with a radio frequency power generation rate, such as 13.56 MHz, is distributed to a network, and the power applied to the plasma chamber is input to the radio frequency radio wave to generate electricity The plasma can be used for etching, painting or deposition operations. The plasma is predicted and repeatable to ensure the quality of the product. The user of the plasma processing needs to continue and according to the detected power Measurement results, processing. Due to the nonlinearity in the plasma processing process, if these harmonic data can be obtained, the data can be priced. At the same time, because of the apparent phase difference between the voltage waveform and the current, there is very little applied power and a simple product of the current. In order to achieve this goal, the sampling rate fs of a junction is used to sample the vibration of the RF voltage. The sampling rate is significantly lower than the applied junction sampling strategy, which has high accuracy and less sampling device for junction. With the RF voltage waveform, the probe will generate the radio wave port as the actual applied waveform. In, for example, processing stress. The ground monitoring is adjusted, and many of the current waves are peak values. They are used to generate a dream chip through a plasma chamber. In order to stop the power supply or stop the harmonics, the voltage between the electric shapes and the connection frequency will be turned off. The substrate inside the impedance horse can achieve this, and the plasma appears. The plasma has a peak value electric sampling circuit to pre-set the amplitude and RF current in the vibration and add the RF power supply 4 (please first Read the precautions on the back and fill in this page)-6-A7 B7 printed by the Zhengong Consumer Cooperative of the Central Bureau of Standards of the Ministry of Economy V. Description of the invention (04) Frequency basic frequency F, if it is 13.56ΜΗζ. This will produce a duplicated waveform of the RF waveform, but the duplicated waveform has a lower overlap frequency fa (aliasing frequenCy), i.e. i〇〇 KHz. The resulting superimposed waveform retains the harmonic data of the original waveform, and the relative phase between the voltage and current waveforms remains in the individual superimposed waveforms. Due to the slow drift and change of the plasma characteristics, there is no obvious change within thousands of cycles of the radio frequency wave, so it can produce an accurate superimposed waveform. The sampling frequency can be selected according to the following formula fs = F / N + / ~ fa / N5 where N is an integer greater than 1. More specifically, if the highest harmonic of interest is the n-th harmonic, assuming: the fifth harmonic of the applied radio frequency power, then the integer N should be chosen to be equal to or greater than the number of harmonics η. As mentioned earlier, the basic frequency of the power supply is normally 13.56 MHz. A typical overlapping frequency can be between about 50 KHz and 250 KHz. In a practical embodiment, the sampling circuit includes a sampling clock operating at the sampling rate fs, and first and second sampling and holding circuits operated by the sampling clock to facilitate sampling of the current and voltage of the radio frequency wave. These samples are digitized into twelve-bit words and combined into a digital input processor or digital input processor called DSP. The voltage and current waveforms are sampled simultaneously. This allows the DSP to generate overlapping representative signals of the voltage and current waveforms at the same time. In a practical example, the junction sampler produces a replica waveform with a superimposed frequency of 100 KHz, which is accurate enough to distinguish the fifth harmonic, and can keep the phase at about one degree. A4 size (21〇297297mm) (please read the precautions on the back before filling in this page). Binding. Order 308778 of the Ministry of Economic Affairs Central Standards Bureau employee consumption cooperation V. Invention description (05) Within the range. Once, the digital samples are stored in an algorithm rule within the Dsp, and the fast Fourier transform (FFT) can be used to operate on these samples to generate a set of frequency domain (frequency d〇fflain) samples, the frequency domain Samples can also be used to control plasma operations or for further analysis. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of an RF plasma device including an RF power generator, an impedance matching network, a plasma chamber, and an RF power probe according to a preferred embodiment of the present invention . Figure 2 is a simplified schematic diagram of the sampling portion of the junction point of the probe embodiment of the present invention. Figs. 3A to 3C explain the radio frequency power waveform applied, the sampling pulse, and the amplitude value of the acquired sample in the embodiment of the present invention. Fig. 4 is the heavy | waveform generated in this embodiment. The preferred embodiment is described in detail. FIG. 1 is a plasma processing apparatus, for example, for etching a silicon wafer or other workpieces. The plasma processing apparatus has an RF power generator that can generate a radio frequency of a specified frequency. The power, for example, 13.56MH; z, is generated by a predetermined electric power level, for example, one kilowatt, and supplies RF power to a matching network 16 along a pipeline 14 '. The output of the matching network 16 is connected to an input of a plasma chamber 20 by a power pipe 18. A probe device 22 is provided above the pipe 18 at the entrance of the plasma chamber 20, and the probe device is used to sample the voltage V- and the current Irf of the applied radio frequency power supply. The collected voltage Vrf and current 1 are along the lines 24 and 26 — 8-4 using the Chinese National Standard (CNS) A4 specification (210X 297 mm) I ^ n > * ^^ 1 ί —l · — 1 ^ 1 HI In 1 ^ 1 \ 〆m —ί HI m * CPlease read the note of the prophet to the back of the prophecy #fill this page '> A7 A7 Printed by the Consumer Cooperative of the Central Standards Bureau of the Ministry of Economic Affairs til V. Description of the invention (06) It is sent to the input of a junction sampler 28, which samples the amplitude of voltage and current at a sampling rate that is slightly slower or faster than the rate of the RF power waveform every N cycles. This generates a set of digital values, which are sent to a digital signal processor or DSP30. The DSP processes these sample values and provides a current and voltage analysis to the output device 32 '. The output device can be connected to control the RF power generator 1 2 via a return line 34 »The details of the junction point sampler 28 Shown in the schematic diagram of Figure 2. In this figure, a sampling clock 36 provides sampling pulses to a voltage sampling and holding circuit 38 and a current sampling and holding circuit 42, and provides an interrupt input signal to Dsp 30. The voltage sample vrf transmitted along the line 24 and the current sample irf transmitted along the line 26 have a fundamental frequency of 1356 mHz, but not a sinusoidal waveform, and may contain more harmonics like the waveform of FIG. 3A. The sampling pulse S (Fig. 3B) occurs at a time interval slightly longer than some predetermined integer number of cycles of the RF power waveform. For example, the sampling pulse may have a time interval equal to one tenth and tenth of a complete cycle, or a time interval of nine and tenths of a full cycle. In either case, the high-speed sampling and holding circuit maintains the amplitude level as shown in Fig. 3 ^, and these continuous sampling levels are combined to produce a combined waveform as shown in Fig. 4. These combined waveforms have the shape of a pulse waveform as shown in Fig. 3a, but are tied at a much lower frequency, for example, the county power mains is one hundredth of the original frequency of 13.56MHz. The description of the present invention is continued with circle 2. The sample-and-hold circuit 38 includes an analog-to-digital converter, or a-d converter, -Γ -----.---, and- ---- order ----- Λ.ξ (please read the precautions on the back and then fill in this page) A7 308778 B7 5. Description of the invention (0 7) (please read the precautions on the back and then fill in this page) ) The converter converts the sampled digital value (3 C) to a digital form with a resolution of at least twelve bits. These samples are sent to a latch circuit 40 via a twelve-bit bus, which connects the twelve-bit sample to the data input port of the DSP 30. The sampling clock 36 is also supplied to the second high-speed sample and hold circuit 42, which also includes an analog-to-digital converter. The circuit 42 samples the amplitude of the RF current sample input from the probe 22 along the line 26. The circuit provides a series of twelve-bit samples to the latch circuit 44, and the latch circuit provides samples as the current data input of the DSP 30. In a practical example, the sampling clock 36 operates at a sampling frequency fs of 2.732MHz. In this way, an aliasing waveform is generated at the fundamental frequency of 100 KHz. The RF sample enters two sample-and-hold circuits 38, 42 '. The sample-and-hold circuit samples the waveforms of voltage Vrf and current Irf at the same time to produce a superimposed waveform of 100 KHz. To achieve this goal, the 13.56MHz waveform is an integer fraction (1 / Ν) of 1 3, 60 0KHz plus (or minus) 100KHz, that is, Industrial and consumer cooperatives print fs = 13,560,000 / N +/- 100,000 / N. If the operator's goal is to obtain reliable information about the fifth harmonic, then the superimposed waveform must have a frequency of 50 OKHz. To achieve this goal, we choose N = 5 and obtain a sampling frequency fs = 13,560,000 / 5 +/- 100,000 / 5. The actual sampling frequency should be determined according to the required resolution. In this 10-page paper scale, the Chinese National Standard (CNS) A4 specification (210X297 mm) is used. A7 B7 V. Description of the invention (08) Cases, the resonance frequency of 500KHz is fully suitable for the sampling of 2.732 / 2 MHz in this example Theoretical limitation "As shown in FIG. 3B, the sampling signal S has a period Ts = 1 / fs, which is about 366 nsec, and the pulse width is about 1 to 5 nsec. The radio frequency wave has a period τ of 1/1 3.56MHz or 73.75nsec (Fig. 3A). In this embodiment, the DSP 30 can generally use a high-speed interrupt channel 'to receive a block of samples at a sampling rate of 2.732 MHz for fast Fourier transform (FFT) or other processing operations. When the samples have been stored in the memory vessel of the DSP 30, an algorithm, such as an FFT ', can be used to calculate the sample block in order to generate a set of samples in the frequency domain. The processed data is then sent to a computer host (not shown in the figure) for further analysis, or for control purposes in order to obtain maximum product quality from plasma processing. HI I! -I In (n.— —l · — ml m ^ ^^ 1 ^^ 1 ^^ 1 11 1 ^ 1 • --¾ (please read the precautions on the back before filling in this page) Central Ministry of Economic Affairs Standard Bureau Peigong Consumer Cooperative Printed
本紙張尺度適用中國國家標準（CNS ) A4規格（210X29*7公釐）The paper size is applicable to China National Standard (CNS) A4 specification (210X29 * 7mm)
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